/* ============================================================
   STEUER-LERNPLATTFORM — Digital Textbook Stylesheet
   Austrian Income Tax Law Learning Platform
   ============================================================
   Table of Contents
   ------------------------------------------------------------
   1.  Custom Properties (Design Tokens)
   2.  CSS Resets & Base
   3.  Typography
   4.  Layout — App Shell
   5.  Topbar
   6.  Main Content Area
   7.  Chapter Spur (Left Indicator)
   8.  Hub Page
   9.  Chapter Slides
   10. Content Typography Elements
   11. Callouts
   12. Feature Grid
   13. Tables
   14. Code Blocks
   15. Decision Cards (Quizzes)
   16. Slide Navigation (Bottom Bar)
   17. Theme Toggle
   18. Font Size Controls
   19. Welcome Page
   20. Exercise Boxes
   21. Lists
   22. Links & Inline Elements
   23. Buttons & Controls
   24. Animations & Transitions
   25. Scrollbar Styling
   26. Selection & Focus
   27. Utility Classes
   28. Print Styles
   29. Responsive — Tablet
   30. Responsive — Mobile
   ============================================================ */


/* ============================================================
   1. CUSTOM PROPERTIES (Design Tokens)
   ============================================================ */

:root {
  /* --- Color Palette — Light Mode (default) --- */
  --color-bg:                #faf9f7;
  --color-bg-secondary:      #f5f3ef;
  --color-bg-tertiary:       #eeecE7;
  --color-surface:           #ffffff;
  --color-surface-hover:     #f8f7f4;

  --color-text-primary:      #1a1a2e;
  --color-text-secondary:    #4a4a6a;
  --color-text-muted:        #7a7a9a;
  --color-text-inverse:      #ffffff;

  --color-accent:            #4f46e5;
  --color-accent-hover:      #4338ca;
  --color-accent-subtle:     #eef2ff;
  --color-accent-tint:       rgba(79, 70, 229, 0.08);
  --color-accent-tint-strong:rgba(79, 70, 229, 0.15);

  --color-border:            #e5e2dc;
  --color-border-light:      #edeae5;
  --color-divider:           #eae7e1;

  --color-code-bg:           #f0ede8;
  --color-code-text:         #3c3a36;

  --color-callout-info:      #3b82f6;
  --color-callout-info-bg:   #eff6ff;
  --color-callout-warning:   #f59e0b;
  --color-callout-warning-bg:#fffbeb;
  --color-callout-tip:       #22c55e;
  --color-callout-tip-bg:    #f0fdf4;
  --color-callout-success:   #22c55e;
  --color-callout-success-bg:#f0fdf4;
  --color-callout-danger:    #ef4444;
  --color-callout-danger-bg: #fef2f2;

  --color-row-alt:           rgba(0, 0, 0, 0.025);
  --color-table-header-bg:   #f5f3ef;

  --color-correct:           #16a34a;
  --color-correct-bg:        #f0fdf4;
  --color-correct-border:    #bbf7d0;
  --color-wrong:             #dc2626;
  --color-wrong-bg:          #fef2f2;
  --color-wrong-border:      #fecaca;

  /* --- Typography --- */
  --font-body:    'Merriweather', Georgia, 'Times New Roman', serif;
  --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono:    'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'Consolas', monospace;

  --font-size-base:   18px;
  --font-size-xs:     0.75rem;   /* 12px */
  --font-size-sm:     0.8333rem; /* ~14px */
  --font-size-md:     1rem;      /* 18px */
  --font-size-lg:     1.1111rem; /* 20px */
  --font-size-xl:     1.2222rem; /* 22px */
  --font-size-2xl:    1.4444rem; /* 26px */
  --font-size-3xl:    1.6667rem; /* 30px */
  --font-size-4xl:    2.4444rem; /* 44px */

  --line-height-body:   1.7;
  --line-height-heading:1.25;

  --letter-spacing-tight:  -0.025em;
  --letter-spacing-normal:  0;
  --letter-spacing-wide:    0.025em;

  /* --- Spacing --- */
  --space-xs:   4px;
  --space-sm:   8px;
  --space-md:   16px;
  --space-lg:   24px;
  --space-xl:   32px;
  --space-2xl:  40px;
  --space-3xl:  56px;
  --space-4xl:  72px;
  --space-5xl:  96px;

  /* --- Layout --- */
  --content-max-width:   940px;
  --content-padding-x:   48px;
  --topbar-height:       56px;
  --spur-width:          52px;

  /* --- Borders --- */
  --radius-sm:   4px;
  --radius-md:   6px;
  --radius-lg:   10px;
  --radius-xl:   14px;
  --radius-full: 9999px;

  /* --- Shadows --- */
  --shadow-xs:   0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-sm:   0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md:   0 4px 6px -1px rgba(0, 0, 0, 0.07), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
  --shadow-lg:   0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
  --shadow-xl:   0 20px 25px -5px rgba(0, 0, 0, 0.08), 0 8px 10px -6px rgba(0, 0, 0, 0.04);

  /* --- Transitions --- */
  --transition-fast:   0.15s ease;
  --transition-base:   0.2s ease;
  --transition-slow:   0.3s ease;
  --transition-theme:  0.2s ease;

  /* --- Z-Index --- */
  --z-base:     1;
  --z-topbar:   100;
  --z-overlay:  200;
  --z-nav:      300;
  --z-toast:    400;
}


/* ============================================================
   1b. DARK MODE CUSTOM PROPERTIES
   ============================================================ */

[data-theme="dark"] {
  --color-bg:              #0f1218;
  --color-bg-secondary:    #151a22;
  --color-bg-tertiary:     #1a2030;
  --color-surface:         #1a2030;
  --color-surface-hover:   #212838;

  --color-text-primary:    #e2e8f0;
  --color-text-secondary:  #94a3b8;
  --color-text-muted:      #64748b;
  --color-text-inverse:    #0f1218;

  --color-accent:          #818cf8;
  --color-accent-hover:    #6366f1;
  --color-accent-subtle:   rgba(129, 140, 248, 0.1);
  --color-accent-tint:     rgba(129, 140, 248, 0.08);
  --color-accent-tint-strong: rgba(129, 140, 248, 0.16);

  --color-border:          #1e293b;
  --color-border-light:    #1a2536;
  --color-divider:         #1e293b;

  --color-code-bg:         #1a1f2e;
  --color-code-text:       #c9d1d9;

  --color-callout-info-bg:    rgba(59, 130, 246, 0.1);
  --color-callout-warning-bg: rgba(245, 158, 11, 0.1);
  --color-callout-tip-bg:     rgba(34, 197, 94, 0.1);
  --color-callout-success-bg: rgba(34, 197, 94, 0.1);
  --color-callout-danger-bg:  rgba(239, 68, 68, 0.1);

  --color-row-alt:           rgba(255, 255, 255, 0.03);
  --color-table-header-bg:   #1a2030;

  --color-correct-bg:        rgba(22, 163, 74, 0.1);
  --color-correct-border:    rgba(22, 163, 74, 0.3);
  --color-wrong-bg:          rgba(220, 38, 38, 0.1);
  --color-wrong-border:      rgba(220, 38, 38, 0.3);

  --shadow-xs:   0 1px 2px rgba(0, 0, 0, 0.2);
  --shadow-sm:   0 1px 3px rgba(0, 0, 0, 0.25), 0 1px 2px rgba(0, 0, 0, 0.15);
  --shadow-md:   0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -2px rgba(0, 0, 0, 0.2);
  --shadow-lg:   0 10px 15px -3px rgba(0, 0, 0, 0.35), 0 4px 6px -4px rgba(0, 0, 0, 0.2);
  --shadow-xl:   0 20px 25px -5px rgba(0, 0, 0, 0.4), 0 8px 10px -6px rgba(0, 0, 0, 0.25);
}


/* ============================================================
   2. CSS RESETS & BASE
   ============================================================ */

*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: var(--font-size-base);
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
  hanging-punctuation: first last;
}

body {
  font-family: var(--font-body);
  font-size: var(--font-size-md);
  line-height: var(--line-height-body);
  color: var(--color-text-primary);
  background-color: var(--color-bg);
  transition:
    background-color var(--transition-theme),
    color var(--transition-theme);
  min-height: 100vh;
  overflow-x: hidden;
}

img,
picture,
video,
canvas,
svg {
  display: block;
  max-width: 100%;
}

input,
button,
textarea,
select {
  font: inherit;
  color: inherit;
}

button {
  cursor: pointer;
  border: none;
  background: none;
}

a {
  color: inherit;
  text-decoration: none;
}

ul,
ol {
  list-style: none;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  line-height: var(--line-height-heading);
  color: var(--color-text-primary);
  overflow-wrap: break-word;
}

p {
  overflow-wrap: break-word;
}

figure {
  margin: 0;
}

hr {
  border: none;
  border-top: 1px solid var(--color-divider);
  margin: var(--space-2xl) 0;
}

strong {
  font-weight: 700;
}

em {
  font-style: italic;
}

abbr[title] {
  text-decoration: underline dotted;
  cursor: help;
}


/* ============================================================
   3. TYPOGRAPHY — Base Scale
   ============================================================ */

h1, .h1 {
  font-family: var(--font-heading);
  font-size: var(--font-size-4xl);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: var(--letter-spacing-tight);
  margin-bottom: var(--space-lg);
  color: var(--color-text-primary);
}

h2, .h2 {
  font-family: var(--font-heading);
  font-size: var(--font-size-3xl);
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: var(--letter-spacing-tight);
  margin-top: var(--space-3xl);
  margin-bottom: var(--space-lg);
  color: var(--color-text-primary);
}

h3, .h3 {
  font-family: var(--font-heading);
  font-size: var(--font-size-2xl);
  font-weight: 600;
  line-height: 1.35;
  margin-top: var(--space-xl);
  margin-bottom: var(--space-md);
  color: var(--color-text-primary);
}

h4, .h4 {
  font-family: var(--font-heading);
  font-size: var(--font-size-xl);
  font-weight: 600;
  line-height: 1.4;
  margin-top: var(--space-lg);
  margin-bottom: var(--space-md);
  color: var(--color-text-primary);
}

h5, .h5 {
  font-family: var(--font-heading);
  font-size: var(--font-size-lg);
  font-weight: 600;
  line-height: 1.45;
  margin-top: var(--space-lg);
  margin-bottom: var(--space-sm);
  color: var(--color-text-primary);
}

h6, .h6 {
  font-family: var(--font-heading);
  font-size: var(--font-size-md);
  font-weight: 600;
  line-height: 1.5;
  margin-top: var(--space-md);
  margin-bottom: var(--space-sm);
  color: var(--color-text-secondary);
}

p {
  margin-bottom: var(--space-lg);
}

p:last-child {
  margin-bottom: 0;
}

small, .text-sm {
  font-size: var(--font-size-sm);
  line-height: 1.5;
}

.text-xs {
  font-size: var(--font-size-xs);
  line-height: 1.5;
}

.text-lg {
  font-size: var(--font-size-lg);
}

.text-xl {
  font-size: var(--font-size-xl);
}

.text-muted {
  color: var(--color-text-muted);
}

.text-secondary {
  color: var(--color-text-secondary);
}

.text-accent {
  color: var(--color-accent);
}

.text-center {
  text-align: center;
}

.text-right {
  text-align: right;
}

.font-mono {
  font-family: var(--font-mono);
}

.font-heading {
  font-family: var(--font-heading);
}

.eyebrow {
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-sm);
}

.lead,
.lead-paragraph {
  font-size: var(--font-size-lg);
  line-height: 1.75;
  color: var(--color-text-secondary);
}

sup {
  font-size: 0.75em;
  vertical-align: super;
  line-height: 0;
}

sub {
  font-size: 0.75em;
  vertical-align: sub;
  line-height: 0;
}

blockquote {
  margin: var(--space-xl) 0;
  padding: var(--space-md) var(--space-lg);
  border-left: 4px solid var(--color-accent);
  background-color: var(--color-bg-secondary);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  font-style: italic;
  color: var(--color-text-secondary);
}

blockquote p {
  margin-bottom: var(--space-sm);
}

blockquote p:last-child {
  margin-bottom: 0;
}

blockquote cite {
  display: block;
  font-size: var(--font-size-sm);
  font-style: normal;
  color: var(--color-text-muted);
  margin-top: var(--space-sm);
}


/* ============================================================
   4. LAYOUT — App Shell
   ============================================================ */

#app {
  display: flex;
  flex-direction: row;
  min-height: 100vh;
  width: 100%;
}


/* ============================================================
   5. TOPBAR
   ============================================================ */

#topbar {
  position: sticky;
  top: 0;
  height: var(--topbar-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-lg);
  background-color: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  z-index: var(--z-topbar);
  transition:
    background-color var(--transition-theme),
    border-color var(--transition-theme);
  flex-shrink: 0;
}

.topbar-left {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  min-width: 0;
  flex: 1;
}

.topbar-right {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  flex-shrink: 0;
}

.topbar-actions {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  flex-shrink: 0;
}

.breadcrumb, .topbar-breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  min-width: 0;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.breadcrumb a, .breadcrumb span, .topbar-breadcrumb a {
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition-base);
}

.breadcrumb a:hover, .topbar-breadcrumb a:hover {
  color: var(--color-accent);
}

.breadcrumb .breadcrumb-sep, .topbar-breadcrumb .separator {
  color: var(--color-text-muted);
  opacity: 0.5;
  margin: 0 2px;
}

.breadcrumb span:last-child, .topbar-breadcrumb .current {
  color: var(--color-text-secondary);
  font-weight: 500;
}

.topbar-title {
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.topbar-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  background-color: var(--color-surface);
  color: var(--color-text-secondary);
  font-size: 16px;
  transition:
    background-color var(--transition-fast),
    color var(--transition-fast),
    border-color var(--transition-fast),
    box-shadow var(--transition-fast);
}

.topbar-btn:hover {
  background-color: var(--color-bg-secondary);
  color: var(--color-text-primary);
  border-color: var(--color-border);
}

.topbar-btn:active {
  transform: scale(0.96);
}

.topbar-btn:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

.topbar-btn[aria-label] {
  position: relative;
}

.topbar-divider {
  width: 1px;
  height: 24px;
  background-color: var(--color-border);
  margin: 0 var(--space-xs);
}

.font-size-controls {
  display: flex;
  align-items: center;
  gap: 2px;
}

.font-size-controls .topbar-btn {
  width: 32px;
  height: 32px;
  font-size: 14px;
  border-radius: var(--radius-sm);
}


/* ============================================================
   6. MAIN CONTENT AREA
   ============================================================ */

#main {
  display: flex;
  flex-direction: column;
  flex-grow: 1;
  height: 100vh;
  overflow: hidden;
}

#main-content {
  flex-grow: 1;
  overflow-y: auto;
  overflow-x: hidden;
  scroll-behavior: smooth;
}

#content {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: var(--space-2xl) var(--content-padding-x) var(--space-4xl);
  width: 100%;
  overflow-wrap: break-word;
}

@media (max-width: 960px) {
  #content {
    padding-left: var(--space-lg);
    padding-right: var(--space-lg);
  }
}


/* ============================================================
   7. CHAPTER SPUR (Left Indicator)
   ============================================================ */

#chapter-spur {
  width: var(--spur-width);
  min-width: var(--spur-width);
  height: 100vh;
  position: sticky;
  top: 0;
  background-color: var(--color-bg-secondary);
  border-right: 1px solid var(--color-border);
  z-index: var(--z-base);
  overflow-y: auto;
  overflow-x: hidden;
}

.hub-view #chapter-spur {
  display: none;
}


/* ============================================================
   8. HUB PAGE
   ============================================================ */

.hub-view {
  display: flex;
  flex-direction: row;
}

.hub-view #content {
  text-align: center;
}

.hub-view #main-content {
  padding-bottom: 0;
}


/* ============================================================
   9. CHAPTER SLIDES
   ============================================================ */

.slide-container {
  position: relative;
  min-height: calc(100vh - var(--topbar-height) - 180px);
}

.slide {
  display: none;
  opacity: 0;
  min-height: 300px;
  max-width: 100%;
  overflow-wrap: break-word;
  word-wrap: break-word;
}

.slide.active {
  display: block;
  opacity: 1;
  animation: slideFadeIn var(--transition-slow) ease forwards;
}

@keyframes slideFadeIn {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.slide-number {
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin-bottom: var(--space-lg);
}

.slide-intro {
  margin-bottom: var(--space-2xl);
}


/* ============================================================
   10. CONTENT TYPOGRAPHY ELEMENTS
   ============================================================ */

.chapter-title {
  font-family: var(--font-heading);
  font-size: var(--font-size-4xl);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: var(--letter-spacing-tight);
  color: var(--color-text-primary);
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-lg);
  border-bottom: 2px solid var(--color-divider);
}

.chapter-subtitle {
  font-family: var(--font-body);
  font-size: var(--font-size-xl);
  font-weight: 400;
  line-height: 1.6;
  color: var(--color-text-muted);
  margin-bottom: var(--space-xl);
  font-style: italic;
}

.chapter-intro {
  font-size: var(--font-size-lg);
  line-height: 1.8;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2xl);
  padding: var(--space-lg);
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--color-accent);
}

.section-title {
  font-family: var(--font-heading);
  font-size: var(--font-size-3xl);
  font-weight: 600;
  line-height: 1.3;
  color: var(--color-text-primary);
  margin-top: var(--space-3xl);
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--color-divider);
}

.section-title .number {
  color: var(--color-accent);
  font-weight: 700;
  margin-right: var(--space-sm);
}

.section-title .number::after {
  content: '';
  display: inline-block;
  width: 8px;
}

.subsection-title {
  font-family: var(--font-heading);
  font-size: var(--font-size-2xl);
  font-weight: 600;
  line-height: 1.35;
  color: var(--color-text-primary);
  margin-top: var(--space-xl);
  margin-bottom: var(--space-md);
}

.paragraph-group {
  margin-bottom: var(--space-xl);
}

.paragraph-group p + p {
  margin-top: calc(-1 * var(--space-sm));
}

.definition {
  padding: var(--space-md) var(--space-lg);
  background-color: var(--color-accent-tint);
  border-left: 2px solid var(--color-accent);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  margin: var(--space-xl) 0;
}

.definition strong,
.definition-term {
  color: var(--color-accent);
}

.legal-reference {
  font-family: var(--font-mono);
  font-size: 0.875em;
  color: var(--color-accent);
  background-color: var(--color-accent-tint);
  padding: 1px 6px;
  border-radius: var(--radius-sm);
  white-space: nowrap;
}

.formula {
  display: block;
  padding: var(--space-lg);
  margin: var(--space-xl) 0;
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-family: var(--font-mono);
  font-size: 0.95em;
  text-align: center;
  overflow-x: auto;
}

.formula-label {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
  text-align: center;
}

.chapter-summary {
  margin-top: var(--space-3xl);
  padding: var(--space-xl);
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
}

.chapter-summary h3 {
  margin-top: 0;
  color: var(--color-accent);
}

.chapter-summary ul {
  margin-top: var(--space-md);
}

.key-point {
  font-weight: 700;
  color: var(--color-text-primary);
  position: relative;
}

.key-point::before {
  content: '';
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--color-accent);
  margin-right: 6px;
  vertical-align: middle;
}

.page-break {
  display: none;
}

@media print {
  .page-break {
    display: block;
    page-break-before: always;
    margin: 0;
    padding: 0;
    height: 0;
    border: none;
  }
}


/* ============================================================
   11. CALLOUTS
   ============================================================ */

.callout {
  margin: var(--space-xl) 0;
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--color-border);
  background-color: var(--color-bg-secondary);
  transition:
    background-color var(--transition-theme),
    border-color var(--transition-theme);
}

.callout-header {
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 600;
  letter-spacing: 0.02em;
  margin-bottom: var(--space-sm);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.callout-header::before {
  font-size: var(--font-size-md);
}

.callout p {
  margin-bottom: var(--space-sm);
  font-size: 0.95em;
}

.callout p:last-child {
  margin-bottom: 0;
}

.callout ul,
.callout ol {
  margin: var(--space-sm) 0 var(--space-sm) var(--space-lg);
}

.callout ul {
  list-style: disc;
}

.callout ol {
  list-style: decimal;
}

.callout li {
  margin-bottom: var(--space-xs);
  font-size: 0.95em;
}

/* Info */
.callout-info {
  border-left-color: var(--color-callout-info);
  background-color: var(--color-callout-info-bg);
}

.callout-info .callout-header {
  color: var(--color-callout-info);
}

.callout-info .callout-header::before {
  content: 'ℹ';
}

/* Warning */
.callout-warning {
  border-left-color: var(--color-callout-warning);
  background-color: var(--color-callout-warning-bg);
}

.callout-warning .callout-header {
  color: var(--color-callout-warning);
}

.callout-warning .callout-header::before {
  content: '⚠';
}

/* Tip */
.callout-tip {
  border-left-color: var(--color-callout-tip);
  background-color: var(--color-callout-tip-bg);
}

.callout-tip .callout-header {
  color: var(--color-callout-tip);
}

.callout-tip .callout-header::before {
  content: '💡';
}

/* Success */
.callout-success {
  border-left-color: var(--color-callout-success);
  background-color: var(--color-callout-success-bg);
}

.callout-success .callout-header {
  color: var(--color-callout-success);
}

.callout-success .callout-header::before {
  content: '✓';
}

/* Danger */
.callout-danger {
  border-left-color: var(--color-callout-danger);
  background-color: var(--color-callout-danger-bg);
}

.callout-danger .callout-header {
  color: var(--color-callout-danger);
}

.callout-danger .callout-header::before {
  content: '✕';
}

/* Note callout — generic variant */
.callout-note {
  border-left-color: var(--color-accent);
  background-color: var(--color-accent-subtle);
}

.callout-note .callout-header {
  color: var(--color-accent);
}

.callout-note .callout-header::before {
  content: '📝';
}

/* Example callout */
.callout-example {
  border-left-color: #8b5cf6;
  background-color: rgba(139, 92, 246, 0.06);
}

.callout-example .callout-header {
  color: #8b5cf6;
}

.callout-example .callout-header::before {
  content: '📘';
}


/* ============================================================
   12. FEATURE GRID
   ============================================================ */

.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-md);
  margin: var(--space-xl) 0;
}

.feature-card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: var(--space-lg);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition:
    box-shadow var(--transition-base),
    border-color var(--transition-base),
    transform var(--transition-base),
    background-color var(--transition-theme);
}

.feature-grid--3col {
  grid-template-columns: repeat(2, 1fr);
}

.feature-card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: var(--space-lg);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition:
    box-shadow var(--transition-base),
    border-color var(--transition-base),
    transform var(--transition-base),
    background-color var(--transition-theme);
}

.feature-card:hover {
  box-shadow: var(--shadow-sm);
  border-color: var(--color-accent);
  transform: translateY(-1px);
}

.feature-icon {
  font-size: 28px;
  margin-bottom: var(--space-md);
  line-height: 1;
}

.feature-title {
  font-family: var(--font-heading);
  font-size: var(--font-size-md);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--space-xs);
}

.feature-description {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: 1.6;
}


/* ============================================================
   13. TABLES
   ============================================================ */

.table-container {
  margin: var(--space-xl) 0;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background-color: var(--color-surface);
  width: 100%;
  max-width: 100%;
}

.table-container table {
  width: 100%;
}

.table-label {
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-sm);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9em;
}

thead {
  background-color: var(--color-table-header-bg);
}

thead th {
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-primary);
  text-align: left;
  padding: var(--space-sm) var(--space-md);
  border-bottom: 2px solid var(--color-border);
  white-space: nowrap;
}

thead th:first-child {
  padding-left: var(--space-md);
}

thead th:last-child {
  padding-right: var(--space-md);
}

tbody td {
  padding: var(--space-sm) var(--space-md);
  border-bottom: 1px solid var(--color-border-light);
  color: var(--color-text-secondary);
  vertical-align: top;
}

tbody td:first-child {
  padding-left: var(--space-md);
}

tbody td:last-child {
  padding-right: var(--space-md);
}

tbody tr:last-child td {
  border-bottom: none;
}

tbody tr:nth-child(even) {
  background-color: var(--color-row-alt);
}

tbody tr:hover {
  background-color: var(--color-accent-tint);
}

.table-number {
  font-family: var(--font-mono);
  font-size: 0.9em;
  color: var(--color-text-muted);
}

.table-highlight {
  background-color: var(--color-accent-tint) !important;
  font-weight: 600;
}

.table-footer {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  padding: var(--space-sm) var(--space-lg);
  background-color: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border);
}


/* ============================================================
   14. CODE BLOCKS
   ============================================================ */

.code-block {
  margin: var(--space-xl) 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  background-color: var(--color-code-bg);
  transition:
    background-color var(--transition-theme),
    border-color var(--transition-theme);
}

.code-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-sm) var(--space-md);
  background-color: var(--color-bg-tertiary);
  border-bottom: 1px solid var(--color-border);
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
}

.code-language {
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  font-weight: 600;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.copy-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-xs) var(--space-sm);
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  background-color: transparent;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition:
    background-color var(--transition-fast),
    color var(--transition-fast),
    border-color var(--transition-fast);
}

.copy-btn:hover {
  background-color: var(--color-surface-hover);
  color: var(--color-text-primary);
  border-color: var(--color-text-muted);
}

.copy-btn:active {
  transform: scale(0.96);
}

.copy-btn.copied {
  color: var(--color-correct);
  border-color: var(--color-correct);
}

.code-block pre {
  margin: 0;
  padding: var(--space-lg);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  background-color: var(--color-code-bg);
  transition: background-color var(--transition-theme);
}

.code-block code {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.7;
  color: var(--color-code-text);
  tab-size: 4;
}

pre {
  margin: var(--space-lg) 0;
  padding: var(--space-lg);
  background-color: var(--color-code-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  transition:
    background-color var(--transition-theme),
    border-color var(--transition-theme);
}

pre code {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.7;
  color: var(--color-code-text);
  background: none;
  padding: 0;
  border-radius: 0;
}

.inline-code,
code:not(pre code) {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background-color: var(--color-code-bg);
  color: var(--color-code-text);
  padding: 2px 7px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border-light);
  white-space: nowrap;
  transition:
    background-color var(--transition-theme),
    border-color var(--transition-theme);
}

kbd {
  font-family: var(--font-mono);
  font-size: 0.8em;
  background-color: var(--color-bg-tertiary);
  border: 1px solid var(--color-border);
  border-bottom-width: 2px;
  border-radius: var(--radius-sm);
  padding: 2px 6px;
  color: var(--color-text-secondary);
}


/* ============================================================
   15. DECISION CARDS (Quizzes)
   ============================================================ */

.decision-card {
  margin: var(--space-xl) 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background-color: var(--color-surface);
  overflow: hidden;
  transition:
    background-color var(--transition-theme),
    border-color var(--transition-theme);
}

.decision-question {
  padding: var(--space-lg) var(--space-xl);
  border-bottom: 1px solid var(--color-border);
  background-color: var(--color-bg-secondary);
}

.decision-question-label {
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-accent);
  margin-bottom: var(--space-sm);
}

.decision-question-text {
  font-size: var(--font-size-md);
  font-weight: 500;
  color: var(--color-text-primary);
  line-height: 1.5;
}

.decision-options {
  padding: var(--space-lg) var(--space-xl);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.decision-option {
  display: flex;
  align-items: flex-start;
  gap: var(--space-md);
  width: 100%;
  padding: var(--space-md) var(--space-lg);
  font-family: var(--font-body);
  font-size: var(--font-size-sm);
  line-height: 1.6;
  color: var(--color-text-primary);
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition:
    background-color var(--transition-fast),
    border-color var(--transition-fast),
    box-shadow var(--transition-fast),
    color var(--transition-fast);
  text-align: left;
}

.decision-option:hover:not(.selected):not(.disabled) {
  background-color: var(--color-surface-hover);
  border-color: var(--color-accent);
  box-shadow: var(--shadow-xs);
}

.decision-option:active:not(.selected):not(.disabled) {
  transform: scale(0.995);
}

.decision-option .option-marker {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  width: 24px;
  height: 24px;
  border-radius: var(--radius-full);
  border: 2px solid var(--color-border);
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  font-weight: 700;
  color: var(--color-text-muted);
  margin-top: 1px;
  transition:
    background-color var(--transition-fast),
    border-color var(--transition-fast),
    color var(--transition-fast);
}

.decision-option:hover:not(.selected):not(.disabled) .option-marker {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.decision-option.selected {
  background-color: var(--color-accent-tint);
  border-color: var(--color-accent);
}

.decision-option.selected .option-marker {
  background-color: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-text-inverse);
}

.decision-option.correct {
  background-color: var(--color-correct-bg);
  border-color: var(--color-correct);
}

.decision-option.correct .option-marker {
  background-color: var(--color-correct);
  border-color: var(--color-correct);
  color: #ffffff;
}

.decision-option.wrong {
  background-color: var(--color-wrong-bg);
  border-color: var(--color-wrong);
}

.decision-option.wrong .option-marker {
  background-color: var(--color-wrong);
  border-color: var(--color-wrong);
  color: #ffffff;
}

.decision-option.disabled {
  cursor: default;
  opacity: 0.7;
}

.decision-option.correct.disabled {
  opacity: 1;
}

.decision-feedback {
  display: none;
  padding: var(--space-lg) var(--space-xl);
  border-top: 1px solid var(--color-border);
  font-size: var(--font-size-sm);
  line-height: 1.7;
}

.decision-feedback.visible {
  display: block;
}

.decision-feedback.correct {
  background-color: var(--color-correct-bg);
  color: var(--color-correct);
}

.decision-feedback.wrong {
  background-color: var(--color-wrong-bg);
  color: var(--color-wrong);
}

.decision-feedback-title {
  font-family: var(--font-heading);
  font-weight: 700;
  margin-bottom: var(--space-xs);
}

.decision-feedback-text {
  color: var(--color-text-secondary);
}

.decision-feedback.explanation {
  background-color: var(--color-accent-subtle);
  color: var(--color-text-primary);
}

.decision-card.answered .decision-option {
  cursor: default;
}

.decision-card.answered .decision-option:hover {
  background-color: inherit;
  border-color: inherit;
  box-shadow: none;
  transform: none;
}

.decision-card.answered .decision-option.correct:hover {
  background-color: var(--color-correct-bg);
  border-color: var(--color-correct);
}

.decision-card.answered .decision-option.wrong:hover {
  background-color: var(--color-wrong-bg);
  border-color: var(--color-wrong);
}


/* ============================================================
   16. SLIDE NAVIGATION (Bottom Bar)
   ============================================================ */

#slide-nav-topbar {
  height: 56px;
  min-height: 56px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-lg);
  padding: 0 var(--space-lg);
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  z-index: var(--z-nav);
  flex-shrink: 0;
  transition:
    background-color var(--transition-theme),
    border-color var(--transition-theme);
}

#slide-nav-topbar:empty {
  display: none;
}

.hub-view #slide-nav-topbar {
  display: none;
}

#slide-nav-topbar.hidden {
  display: none;
}

.slide-nav-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-lg);
  max-width: var(--content-max-width);
  width: 100%;
}

.slide-prev,
.slide-next {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition:
    background-color var(--transition-fast),
    color var(--transition-fast),
    border-color var(--transition-fast),
    box-shadow var(--transition-fast);
  white-space: nowrap;
}

.slide-prev:hover,
.slide-next:hover {
  background-color: var(--color-accent);
  color: #ffffff;
  border-color: var(--color-accent);
}

.slide-prev:active,
.slide-next:active {
  transform: scale(0.97);
}

.slide-prev:disabled,
.slide-next:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  background-color: var(--color-surface);
  color: var(--color-text-muted);
  border-color: var(--color-border);
}

.slide-prev:disabled:hover,
.slide-next:disabled:hover {
  background-color: var(--color-surface);
  color: var(--color-text-muted);
  border-color: var(--color-border);
  transform: none;
}

.slide-prev svg,
.slide-next svg {
  width: 16px;
  height: 16px;
}

.slide-dots {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-shrink: 0;
}

.slide-dot {
  width: 8px;
  height: 8px;
  border-radius: var(--radius-full);
  background-color: var(--color-border);
  border: none;
  cursor: pointer;
  padding: 0;
  transition:
    background-color var(--transition-fast),
    transform var(--transition-fast),
    width var(--transition-fast);
}

.slide-dot:hover {
  background-color: var(--color-text-muted);
}

.slide-dot.active {
  background-color: var(--color-accent);
  width: 20px;
  border-radius: var(--radius-full);
}

.slide-dot:active {
  transform: scale(0.9);
}

.slide-counter {
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  white-space: nowrap;
}

.slide-progress-bar {
  position: absolute;
  top: 0;
  left: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-accent-hover));
  transition: width 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}


/* ============================================================
   17. THEME TOGGLE
   ============================================================ */

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  background-color: var(--color-surface);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition:
    background-color var(--transition-fast),
    color var(--transition-fast),
    border-color var(--transition-fast);
  position: relative;
  overflow: hidden;
}

.theme-toggle:hover {
  background-color: var(--color-bg-secondary);
  color: var(--color-accent);
  border-color: var(--color-accent);
}

.theme-toggle:active {
  transform: scale(0.95);
}

.theme-toggle:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

.theme-icon-sun,
.theme-icon-moon {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  transition:
    opacity var(--transition-base),
    transform var(--transition-base);
}

.theme-icon-sun {
  opacity: 0;
  transform: rotate(-90deg) scale(0.5);
}

.theme-icon-moon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

[data-theme="dark"] .theme-icon-sun {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

[data-theme="dark"] .theme-icon-moon {
  opacity: 0;
  transform: rotate(90deg) scale(0.5);
}


/* ============================================================
   18. FONT SIZE CONTROLS
   ============================================================ */

.font-size-controls {
  display: flex;
  align-items: center;
  gap: 2px;
}

.font-size-decrease,
.font-size-increase {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  background-color: var(--color-surface);
  color: var(--color-text-secondary);
  font-family: var(--font-heading);
  font-size: 14px;
  cursor: pointer;
  transition:
    background-color var(--transition-fast),
    color var(--transition-fast),
    border-color var(--transition-fast);
}

.font-size-decrease:hover,
.font-size-increase:hover {
  background-color: var(--color-bg-secondary);
  color: var(--color-text-primary);
}

.font-size-decrease:active,
.font-size-increase:active {
  transform: scale(0.95);
}

/* Font size scale applied to html */
html.font-size-sm {
  font-size: 16px;
}

html.font-size-md {
  font-size: 18px;
}

html.font-size-lg {
  font-size: 20px;
}

html.font-size-xl {
  font-size: 22px;
}


/* ============================================================
   19. WELCOME PAGE
   ============================================================ */

.welcome-hero {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: var(--space-4xl) 0 var(--space-2xl);
}

.welcome-hero .welcome-icon {
  font-size: 64px;
  margin-bottom: var(--space-xl);
  line-height: 1;
}

.welcome-hero h1 {
  font-size: var(--font-size-4xl);
  max-width: 600px;
  margin-bottom: var(--space-md);
}

.welcome-hero .welcome-subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  max-width: 520px;
  line-height: 1.75;
  margin-bottom: var(--space-2xl);
}

.welcome-cta {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl);
  font-family: var(--font-heading);
  font-size: var(--font-size-md);
  font-weight: 600;
  color: #ffffff;
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-hover));
  border: none;
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition:
    box-shadow var(--transition-base),
    transform var(--transition-base);
  text-decoration: none;
  box-shadow: var(--shadow-md);
}

.welcome-cta:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.welcome-cta:active {
  transform: translateY(0);
  box-shadow: var(--shadow-sm);
}

.welcome-cta:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}

.welcome-cta svg {
  width: 18px;
  height: 18px;
}

.welcome-features {
  margin: var(--space-3xl) 0;
}

.welcome-features h2 {
  text-align: center;
  margin-bottom: var(--space-xl);
}

.welcome-note {
  display: flex;
  align-items: flex-start;
  gap: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  margin: var(--space-lg) 0;
  background-color: var(--color-accent-subtle);
  border: 1px solid var(--color-accent-tint-strong);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.welcome-note .note-icon {
  flex-shrink: 0;
  font-size: var(--font-size-lg);
  line-height: 1;
}

.welcome-steps {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  margin: var(--space-2xl) 0;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}

.welcome-step {
  display: flex;
  gap: var(--space-lg);
  align-items: flex-start;
}

.welcome-step-number {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-hover));
  color: #ffffff;
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 700;
  flex-shrink: 0;
}

.welcome-step-content {
  padding-top: var(--space-xs);
}

.welcome-step-content h3 {
  font-size: var(--font-size-md);
  margin-top: 0;
  margin-bottom: var(--space-xs);
}

.welcome-step-content p {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin-bottom: 0;
}


/* ============================================================
   20. EXERCISE BOXES
   ============================================================ */

.exercise-box {
  margin: var(--space-xl) 0;
  border: 2px solid var(--color-accent);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background-color: var(--color-surface);
}

.exercise-header {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md) var(--space-xl);
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-hover));
  color: #ffffff;
}

.exercise-icon {
  font-size: 20px;
  line-height: 1;
}

.exercise-title {
  font-family: var(--font-heading);
  font-size: var(--font-size-md);
  font-weight: 700;
  color: #ffffff;
}

.exercise-body {
  padding: var(--space-xl);
}

.exercise-body p {
  margin-bottom: var(--space-md);
}

.exercise-body p:last-child {
  margin-bottom: 0;
}

.exercise-input {
  margin-top: var(--space-md);
}

.exercise-input label {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-sm);
}

.exercise-input input,
.exercise-input textarea {
  width: 100%;
  padding: var(--space-md);
  font-family: var(--font-mono);
  font-size: var(--font-size-sm);
  color: var(--color-text-primary);
  background-color: var(--color-code-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition:
    border-color var(--transition-fast),
    box-shadow var(--transition-fast),
    background-color var(--transition-theme);
}

.exercise-input input:focus,
.exercise-input textarea:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-tint);
}

.exercise-input textarea {
  min-height: 120px;
  resize: vertical;
}

.exercise-actions {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-top: var(--space-lg);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
}

.exercise-hint {
  display: none;
  margin-top: var(--space-md);
  padding: var(--space-md);
  background-color: var(--color-callout-warning-bg);
  border-left: 3px solid var(--color-callout-warning);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  font-size: var(--font-size-sm);
}

.exercise-hint.visible {
  display: block;
}

.exercise-result {
  display: none;
  margin-top: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
}

.exercise-result.visible {
  display: block;
}

.exercise-result.correct {
  background-color: var(--color-correct-bg);
  color: var(--color-correct);
  border: 1px solid var(--color-correct-border);
}

.exercise-result.wrong {
  background-color: var(--color-wrong-bg);
  color: var(--color-wrong);
  border: 1px solid var(--color-wrong-border);
}


/* ============================================================
   21. LISTS
   ============================================================ */

ul,
ol {
  margin: var(--space-md) 0 var(--space-lg) var(--space-lg);
}

ul {
  list-style-type: disc;
}

ol {
  list-style-type: decimal;
}

li {
  margin-bottom: var(--space-sm);
  padding-left: var(--space-xs);
}

li:last-child {
  margin-bottom: 0;
}

li > ul,
li > ol {
  margin-top: var(--space-sm);
  margin-bottom: 0;
}

ul ul {
  list-style-type: circle;
}

ul ul ul {
  list-style-type: square;
}

ol ol {
  list-style-type: lower-alpha;
}

ol ol ol {
  list-style-type: lower-roman;
}

.list-clean {
  list-style: none;
  margin-left: 0;
  padding-left: 0;
}

.list-clean li {
  padding-left: 0;
}

.list-check {
  list-style: none;
  margin-left: 0;
}

.list-check li {
  padding-left: var(--space-xl);
  position: relative;
}

.list-check li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--color-accent);
  font-weight: 700;
}

.list-numbered-clear {
  list-style: none;
  margin-left: 0;
  counter-reset: list-counter;
}

.list-numbered-clear li {
  padding-left: var(--space-xl);
  position: relative;
  counter-increment: list-counter;
}

.list-numbered-clear li::before {
  content: counter(list-counter) '.';
  position: absolute;
  left: 0;
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--color-accent);
}

.definition-list {
  margin: var(--space-lg) 0;
}

.definition-list dt {
  font-weight: 700;
  color: var(--color-text-primary);
  margin-top: var(--space-md);
}

.definition-list dd {
  color: var(--color-text-secondary);
  margin-left: var(--space-lg);
  margin-top: var(--space-xs);
  padding-left: var(--space-sm);
  border-left: 2px solid var(--color-border);
}


/* ============================================================
   22. LINKS & INLINE ELEMENTS
   ============================================================ */

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

a:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

.external-link::after {
  content: '↗';
  font-size: 0.75em;
  margin-left: 3px;
  vertical-align: super;
}

mark,
.highlight {
  background-color: var(--color-accent-tint-strong);
  color: var(--color-text-primary);
  padding: 1px 4px;
  border-radius: var(--radius-sm);
}

.tag {
  display: inline-flex;
  align-items: center;
  padding: 2px 10px;
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  font-weight: 600;
  border-radius: var(--radius-full);
  background-color: var(--color-accent-subtle);
  color: var(--color-accent);
  white-space: nowrap;
}

.tag-green {
  background-color: var(--color-callout-tip-bg);
  color: var(--color-callout-tip);
}

.tag-red {
  background-color: var(--color-callout-danger-bg);
  color: var(--color-callout-danger);
}

.tag-blue {
  background-color: var(--color-callout-info-bg);
  color: var(--color-callout-info);
}

.tag-amber {
  background-color: var(--color-callout-warning-bg);
  color: var(--color-callout-warning);
}

.divider {
  border: none;
  border-top: 1px solid var(--color-divider);
  margin: var(--space-2xl) 0;
}

.divider-label {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin: var(--space-2xl) 0;
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.divider-label::before,
.divider-label::after {
  content: '';
  flex: 1;
  height: 1px;
  background-color: var(--color-divider);
}


/* ============================================================
   23. BUTTONS & CONTROLS
   ============================================================ */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-lg);
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 500;
  line-height: 1.5;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition:
    background-color var(--transition-fast),
    color var(--transition-fast),
    border-color var(--transition-fast),
    box-shadow var(--transition-fast),
    transform var(--transition-fast);
  text-decoration: none;
  white-space: nowrap;
}

.btn:active {
  transform: scale(0.97);
}

.btn:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

.btn-primary {
  color: #ffffff;
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-hover));
  border-color: var(--color-accent);
}

.btn-primary:hover {
  text-decoration: none;
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  color: var(--color-text-primary);
  background-color: var(--color-surface);
  border-color: var(--color-border);
}

.btn-secondary:hover {
  text-decoration: none;
  background-color: var(--color-bg-secondary);
  border-color: var(--color-text-muted);
}

.btn-ghost {
  color: var(--color-text-secondary);
  background-color: transparent;
  border-color: transparent;
}

.btn-ghost:hover {
  text-decoration: none;
  background-color: var(--color-bg-secondary);
  color: var(--color-text-primary);
}

.btn-sm {
  padding: var(--space-xs) var(--space-md);
  font-size: var(--font-size-xs);
}

.btn-lg {
  padding: var(--space-md) var(--space-xl);
  font-size: var(--font-size-md);
}

.btn-icon {
  padding: var(--space-sm);
}

.btn-icon svg {
  width: 18px;
  height: 18px;
}

.btn:disabled,
.btn.disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}

.btn-group {
  display: flex;
  gap: var(--space-sm);
}


/* ============================================================
   24. ANIMATIONS & TRANSITIONS
   ============================================================ */

.fade-in {
  animation: fadeIn var(--transition-slow) ease forwards;
}

.fade-in-up {
  animation: fadeInUp var(--transition-slow) ease forwards;
}

.fade-in-delayed {
  animation: fadeIn var(--transition-slow) ease 0.1s forwards;
  opacity: 0;
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slideInLeft {
  from {
    opacity: 0;
    transform: translateX(-16px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes slideInRight {
  from {
    opacity: 0;
    transform: translateX(16px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.6;
  }
}

.animate-slide-in-left {
  animation: slideInLeft var(--transition-slow) ease forwards;
}

.animate-slide-in-right {
  animation: slideInRight var(--transition-slow) ease forwards;
}

.transition-theme {
  transition:
    background-color var(--transition-theme),
    color var(--transition-theme),
    border-color var(--transition-theme);
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  html {
    scroll-behavior: auto;
  }
}


/* ============================================================
   25. SCROLLBAR STYLING
   ============================================================ */

::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background-color: var(--color-border);
  border-radius: var(--radius-full);
  border: 2px solid transparent;
  background-clip: padding-box;
}

::-webkit-scrollbar-thumb:hover {
  background-color: var(--color-text-muted);
  border: 1px solid transparent;
  background-clip: padding-box;
}

::-webkit-scrollbar-corner {
  background: transparent;
}

/* Firefox scrollbar */
* {
  scrollbar-width: thin;
  scrollbar-color: var(--color-border) transparent;
}


/* ============================================================
   26. SELECTION & FOCUS
   ============================================================ */

::selection {
  background-color: var(--color-accent-tint-strong);
  color: var(--color-text-primary);
}

::-moz-selection {
  background-color: var(--color-accent-tint-strong);
  color: var(--color-text-primary);
}

:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

:focus:not(:focus-visible) {
  outline: none;
}


/* ============================================================
   27. UTILITY CLASSES
   ============================================================ */

/* Display */
.d-none { display: none !important; }
.d-block { display: block !important; }
.d-flex { display: flex !important; }
.d-inline-flex { display: inline-flex !important; }
.d-grid { display: grid !important; }

/* Flex */
.flex-row { flex-direction: row; }
.flex-col { flex-direction: column; }
.flex-wrap { flex-wrap: wrap; }
.flex-1 { flex: 1; }
.flex-shrink-0 { flex-shrink: 0; }
.items-center { align-items: center; }
.items-start { align-items: flex-start; }
.items-end { align-items: flex-end; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.justify-end { justify-content: flex-end; }

/* Gap */
.gap-xs { gap: var(--space-xs); }
.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }
.gap-lg { gap: var(--space-lg); }
.gap-xl { gap: var(--space-xl); }

/* Margin */
.m-0 { margin: 0 !important; }
.mt-0 { margin-top: 0 !important; }
.mt-sm { margin-top: var(--space-sm) !important; }
.mt-md { margin-top: var(--space-md) !important; }
.mt-lg { margin-top: var(--space-lg) !important; }
.mt-xl { margin-top: var(--space-xl) !important; }
.mt-2xl { margin-top: var(--space-2xl) !important; }
.mt-3xl { margin-top: var(--space-3xl) !important; }
.mb-0 { margin-bottom: 0 !important; }
.mb-sm { margin-bottom: var(--space-sm) !important; }
.mb-md { margin-bottom: var(--space-md) !important; }
.mb-lg { margin-bottom: var(--space-lg) !important; }
.mb-xl { margin-bottom: var(--space-xl) !important; }
.mb-2xl { margin-bottom: var(--space-2xl) !important; }
.mx-auto { margin-left: auto; margin-right: auto; }

/* Padding */
.p-0 { padding: 0 !important; }
.p-md { padding: var(--space-md) !important; }
.p-lg { padding: var(--space-lg) !important; }
.p-xl { padding: var(--space-xl) !important; }
.py-xl { padding-top: var(--space-xl) !important; padding-bottom: var(--space-xl) !important; }

/* Width */
.w-full { width: 100% !important; }
.max-w-content { max-width: var(--content-max-width); }

/* Overflow */
.overflow-hidden { overflow: hidden; }
.overflow-auto { overflow: auto; }

/* Visibility */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* Truncation */
.truncate {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.line-clamp-2 {
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.line-clamp-3 {
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* Border */
.rounded-sm { border-radius: var(--radius-sm); }
.rounded-md { border-radius: var(--radius-md); }
.rounded-lg { border-radius: var(--radius-lg); }
.rounded-full { border-radius: var(--radius-full); }

.border { border: 1px solid var(--color-border); }
.border-t { border-top: 1px solid var(--color-border); }
.border-b { border-bottom: 1px solid var(--color-border); }

/* Shadow */
.shadow-sm { box-shadow: var(--shadow-sm); }
.shadow-md { box-shadow: var(--shadow-md); }
.shadow-lg { box-shadow: var(--shadow-lg); }


/* ============================================================
   28. PRINT STYLES
   ============================================================ */

@media print {
  *,
  *::before,
  *::after {
    background: transparent !important;
    color: #000 !important;
    box-shadow: none !important;
    text-shadow: none !important;
  }

  body {
    font-size: 12pt;
    line-height: 1.5;
    color: #000;
  }

  a,
  a:visited {
    text-decoration: underline;
    color: #000;
  }

  a[href^="http"]::after {
    content: " (" attr(href) ")";
    font-size: 0.8em;
    color: #555;
  }

  #topbar,
  #slide-nav-topbar,
  #chapter-spur,
  .theme-toggle,
  .font-size-controls,
  .copy-btn,
  .slide-prev,
  .slide-next,
  .slide-dots,
  .slide-counter,
  .slide-progress-bar,
  .btn,
  .decision-option {
    display: none !important;
  }

  #app {
    display: block;
  }

  #main {
    padding-top: 0;
  }

  #content {
    max-width: 100%;
    padding: 0;
  }

  .slide {
    display: block !important;
    opacity: 1 !important;
    page-break-inside: avoid;
  }

  .slide:not(:last-child) {
    border-bottom: 1px solid #ccc;
    padding-bottom: 24pt;
    margin-bottom: 24pt;
  }

  .callout {
    border: 1px solid #ccc;
    border-left-width: 4px;
  }

  .code-block {
    border: 1px solid #ccc;
  }

  pre {
    border: 1px solid #ccc;
    white-space: pre-wrap;
    word-wrap: break-word;
  }

  table {
    border-collapse: collapse;
  }

  table th,
  table td {
    border: 1px solid #ccc;
    padding: 8px;
  }

  thead {
    background-color: #eee !important;
  }

  img {
    max-width: 100% !important;
  }

  h1, h2, h3 {
    page-break-after: avoid;
    break-after: avoid;
  }

  .callout,
  .exercise-box,
  .decision-card,
  .table-container,
  .code-block,
  blockquote {
    page-break-inside: avoid;
    break-inside: avoid;
  }
}


/* ============================================================
   29. RESPONSIVE — Tablet (max-width: 960px)
   ============================================================ */

@media (max-width: 960px) {
  :root {
    --content-padding-x: 32px;
  }

  h1, .h1, .chapter-title {
    font-size: 2rem;
  }

  h2, .h2, .section-title {
    font-size: 1.5rem;
  }

  h3, .h3, .subsection-title {
    font-size: 1.25rem;
  }

  .hub-card {
    padding: var(--space-md) var(--space-md);
  }

  .feature-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-md);
  }

  .welcome-hero h1 {
    font-size: 2rem;
  }
}


/* ============================================================
   30. RESPONSIVE — Mobile (max-width: 640px)
   ============================================================ */

@media (max-width: 640px) {
  :root {
    --content-padding-x: 20px;
    --topbar-height: 50px;
  }

  html {
    font-size: 16px;
  }

  body {
    font-size: 1rem;
  }

  h1, .h1, .chapter-title {
    font-size: 1.75rem;
  }

  h2, .h2, .section-title {
    font-size: 1.35rem;
    margin-top: var(--space-xl);
  }

  h3, .h3, .subsection-title {
    font-size: 1.15rem;
  }

  .chapter-subtitle {
    font-size: 1rem;
  }

  .chapter-intro {
    font-size: 1rem;
    padding: var(--space-md);
  }

  #content {
    padding-top: var(--space-lg);
    padding-bottom: var(--space-3xl);
  }

  #topbar {
    padding: 0 var(--space-md);
  }

  .topbar-breadcrumb {
    font-size: 0.7rem;
  }

  .topbar-title {
    font-size: 0.7rem;
  }

  .topbar-divider {
    display: none;
  }

  .hub-header h1 {
    font-size: 1.75rem;
  }

  .hub-header .hub-description {
    font-size: 1rem;
  }

  .hub-section-title {
    font-size: var(--font-size-xs);
  }

  .hub-card {
    padding: var(--space-md);
  }

  .feature-grid {
    grid-template-columns: 1fr;
  }

  .welcome-hero {
    padding: var(--space-2xl) 0;
  }

  .welcome-hero .welcome-icon {
    font-size: 48px;
  }

  .welcome-hero h1 {
    font-size: 1.75rem;
  }

  .welcome-cta {
    width: 100%;
    justify-content: center;
  }

  .callout {
    padding: var(--space-md);
  }

  .decision-question {
    padding: var(--space-md);
  }

  .decision-options {
    padding: var(--space-md);
  }

  .decision-option {
    padding: var(--space-sm) var(--space-md);
  }

  .decision-feedback {
    padding: var(--space-md);
  }

  .exercise-header {
    padding: var(--space-sm) var(--space-md);
  }

  .exercise-body {
    padding: var(--space-md);
  }

  #slide-nav-topbar {
    height: 50px;
  }

  .slide-prev,
  .slide-next {
    padding: var(--space-sm);
    font-size: var(--font-size-xs);
  }

  .slide-prev .btn-label,
  .slide-next .btn-label {
    display: none;
  }

  .slide-dots {
    gap: 4px;
  }

  .slide-dot {
    width: 6px;
    height: 6px;
  }

  .slide-dot.active {
    width: 16px;
  }

  table {
    font-size: 0.85em;
  }

  thead th,
  tbody td {
    padding: var(--space-sm) var(--space-md);
  }

  .code-block pre {
    padding: var(--space-md);
  }

  .code-block code {
    font-size: 0.8rem;
  }

  .blockquote {
    padding: var(--space-md);
  }

  .formula {
    padding: var(--space-md);
    font-size: 0.85em;
  }

  .slide-container {
    min-height: auto;
  }

  .font-size-controls {
    display: none;
  }

  #chapter-spur {
    display: none !important;
  }
}


/* ============================================================
   31. ADDITIONAL COMPONENTS — Status Indicators
   ============================================================ */

.progress-ring {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
}

.progress-ring-circle {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  background: conic-gradient(
    var(--color-accent) var(--progress, 0%),
    var(--color-bg-tertiary) var(--progress, 0%)
  );
  position: relative;
}

.progress-ring-circle::after {
  content: '';
  position: absolute;
  inset: 3px;
  background-color: var(--color-surface);
  border-radius: var(--radius-full);
}

.progress-ring-label {
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.completion-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-xs) var(--space-md);
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  font-weight: 600;
  color: var(--color-correct);
  background-color: var(--color-correct-bg);
  border-radius: var(--radius-full);
}

.completion-badge::before {
  content: '✓';
  font-weight: 700;
}


/* ============================================================
   32. TOOLTIP
   ============================================================ */

[data-tooltip] {
  position: relative;
}

[data-tooltip]::after {
  content: attr(data-tooltip);
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%) translateY(4px);
  padding: var(--space-xs) var(--space-sm);
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  color: #ffffff;
  background-color: var(--color-text-primary);
  border-radius: var(--radius-sm);
  white-space: nowrap;
  pointer-events: none;
  opacity: 0;
  transition:
    opacity var(--transition-fast),
    transform var(--transition-fast);
  z-index: var(--z-toast);
}

[data-tooltip]:hover::after {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

[data-tooltip-position="bottom"]::after {
  top: calc(100% + 8px);
  bottom: auto;
}


/* ============================================================
   33. FOOTER / CHAPTER END
   ============================================================ */

.chapter-end {
  margin-top: var(--space-4xl);
  padding-top: var(--space-2xl);
  border-top: 2px solid var(--color-divider);
  text-align: center;
}

.chapter-end-icon {
  font-size: 40px;
  margin-bottom: var(--space-md);
}

.chapter-end-title {
  font-family: var(--font-heading);
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--space-sm);
}

.chapter-end-text {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-lg);
}

.chapter-nav {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  margin-top: var(--space-xl);
}

.chapter-nav-link {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl);
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-accent);
  background-color: var(--color-accent-subtle);
  border: 1px solid var(--color-accent-tint-strong);
  border-radius: var(--radius-lg);
  transition:
    background-color var(--transition-fast),
    box-shadow var(--transition-fast),
    transform var(--transition-fast);
  text-decoration: none;
}

.chapter-nav-link:hover {
  background-color: var(--color-accent);
  color: #ffffff;
  box-shadow: var(--shadow-md);
  text-decoration: none;
  transform: translateY(-1px);
}

.chapter-nav-link:active {
  transform: translateY(0);
}

.chapter-nav-link svg {
  width: 16px;
  height: 16px;
}


/* ============================================================
   34. SEARCH (if applicable)
   ============================================================ */

.search-overlay {
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: var(--z-overlay);
  display: none;
  align-items: flex-start;
  justify-content: center;
  padding-top: 20vh;
}

.search-overlay.active {
  display: flex;
}

.search-dialog {
  width: 90%;
  max-width: 560px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  overflow: hidden;
}

.search-input-wrapper {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-lg);
  border-bottom: 1px solid var(--color-border);
}

.search-input-wrapper svg {
  width: 20px;
  height: 20px;
  color: var(--color-text-muted);
  flex-shrink: 0;
}

.search-input {
  flex: 1;
  border: none;
  background: transparent;
  font-family: var(--font-body);
  font-size: var(--font-size-md);
  color: var(--color-text-primary);
  outline: none;
}

.search-input::placeholder {
  color: var(--color-text-muted);
}

.search-results {
  max-height: 360px;
  overflow-y: auto;
  padding: var(--space-sm);
}

.search-result-item {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background-color var(--transition-fast);
}

.search-result-item:hover {
  background-color: var(--color-bg-secondary);
}

.search-result-title {
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-primary);
}

.search-result-excerpt {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  line-height: 1.5;
}

.search-empty {
  padding: var(--space-2xl);
  text-align: center;
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.search-kbd {
  font-family: var(--font-mono);
  font-size: var(--font-size-xs);
  padding: 2px 6px;
  background-color: var(--color-bg-tertiary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
}


/* ============================================================
   35. SKELETON LOADING
   ============================================================ */

.skeleton {
  background: linear-gradient(
    90deg,
    var(--color-bg-secondary) 25%,
    var(--color-bg-tertiary) 50%,
    var(--color-bg-secondary) 75%
  );
  background-size: 200% 100%;
  animation: skeleton-pulse 1.5s ease-in-out infinite;
  border-radius: var(--radius-sm);
}

.skeleton-text {
  height: 16px;
  margin-bottom: var(--space-sm);
  border-radius: var(--radius-sm);
}

.skeleton-text:last-child {
  width: 75%;
}

.skeleton-heading {
  height: 32px;
  width: 60%;
  margin-bottom: var(--space-md);
}

.skeleton-paragraph {
  height: 80px;
  margin-bottom: var(--space-lg);
}

@keyframes skeleton-pulse {
  0% {
    background-position: 200% 0;
  }
  100% {
    background-position: -200% 0;
  }
}


/* ============================================================
   36. NOTIFICATION TOAST
   ============================================================ */

.toast-container {
  position: fixed;
  bottom: var(--space-lg);
  right: var(--space-lg);
  z-index: var(--z-toast);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  pointer-events: none;
}

.toast {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  color: var(--color-text-primary);
  pointer-events: auto;
  animation: toastIn var(--transition-slow) ease forwards;
  max-width: 380px;
}

.toast.hiding {
  animation: toastOut var(--transition-base) ease forwards;
}

.toast-icon {
  font-size: var(--font-size-lg);
  flex-shrink: 0;
}

.toast-message {
  flex: 1;
  min-width: 0;
}

.toast-close {
  flex-shrink: 0;
  color: var(--color-text-muted);
  padding: var(--space-xs);
  border-radius: var(--radius-sm);
  transition: background-color var(--transition-fast);
}

.toast-close:hover {
  background-color: var(--color-bg-secondary);
  color: var(--color-text-primary);
}

.toast-success {
  border-left: 4px solid var(--color-correct);
}

.toast-error {
  border-left: 4px solid var(--color-wrong);
}

.toast-info {
  border-left: 4px solid var(--color-callout-info);
}

@keyframes toastIn {
  from {
    opacity: 0;
    transform: translateX(16px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes toastOut {
  from {
    opacity: 1;
    transform: translateX(0);
  }
  to {
    opacity: 0;
    transform: translateX(16px);
  }
}


/* ============================================================
   37. LEGAL CITATION STYLING
   ============================================================ */

.legal-citation {
  font-family: var(--font-mono);
  font-size: 0.85em;
  color: var(--color-accent);
  background-color: var(--color-accent-tint);
  padding: 1px 6px;
  border-radius: var(--radius-sm);
  white-space: nowrap;
  cursor: help;
  transition:
    background-color var(--transition-fast),
    color var(--transition-fast);
}

.legal-citation:hover {
  background-color: var(--color-accent-tint-strong);
}

.legal-section {
  margin: var(--space-xl) 0;
  padding: var(--space-lg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background-color: var(--color-surface);
}

.legal-section-header {
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 700;
  color: var(--color-accent);
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--color-border);
}

.legal-text {
  font-family: var(--font-body);
  font-size: 0.95em;
  line-height: 1.8;
  color: var(--color-text-secondary);
}

.legal-text .paragraph-marker {
  font-weight: 700;
  color: var(--color-text-primary);
  margin-right: var(--space-sm);
}

.legal-amendment {
  display: inline-block;
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  font-style: italic;
  margin-left: var(--space-sm);
}


/* ============================================================
   38. COMPARISON / SIDE-BY-SIDE
   ============================================================ */

.comparison {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
  margin: var(--space-xl) 0;
}

.comparison-item {
  padding: var(--space-lg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background-color: var(--color-surface);
}

.comparison-label {
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-sm);
  border-bottom: 2px solid var(--color-accent);
}

.comparison-vs {
  display: flex;
  align-items: center;
  justify-content: center;
}

.comparison-vs span {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  background-color: var(--color-accent);
  color: #ffffff;
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  font-weight: 700;
}

@media (max-width: 640px) {
  .comparison {
    grid-template-columns: 1fr;
  }

  .comparison-vs {
    display: none;
  }
}


/* ============================================================
   39. STEP / PROCESS INDICATOR
   ============================================================ */

.steps {
  margin: var(--space-xl) 0;
  counter-reset: step-counter;
}

.step-item {
  display: flex;
  gap: var(--space-lg);
  position: relative;
  padding-bottom: var(--space-xl);
  counter-increment: step-counter;
}

.step-item:last-child {
  padding-bottom: 0;
}

.step-item::before {
  content: '';
  position: absolute;
  left: 18px;
  top: 40px;
  bottom: 0;
  width: 2px;
  background-color: var(--color-border);
}

.step-item:last-child::before {
  display: none;
}

.step-marker {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: var(--radius-full);
  background-color: var(--color-accent);
  color: #ffffff;
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 700;
  flex-shrink: 0;
  position: relative;
  z-index: 1;
}

.step-marker::after {
  content: counter(step-counter);
}

.step-content {
  padding-top: var(--space-sm);
  flex: 1;
}

.step-content h4 {
  margin-top: 0;
  font-size: var(--font-size-md);
  margin-bottom: var(--space-xs);
}

.step-content p {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}


/* ============================================================
   40. ACCORDION (Collapsible Sections)
   ============================================================ */

.accordion {
  margin: var(--space-xl) 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background-color: var(--color-surface);
}

.accordion-item {
  border-bottom: 1px solid var(--color-border);
}

.accordion-item:last-child {
  border-bottom: none;
}

.accordion-trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: var(--space-lg);
  font-family: var(--font-heading);
  font-size: var(--font-size-md);
  font-weight: 600;
  color: var(--color-text-primary);
  background: none;
  border: none;
  cursor: pointer;
  transition:
    background-color var(--transition-fast),
    color var(--transition-fast);
  text-align: left;
}

.accordion-trigger:hover {
  background-color: var(--color-bg-secondary);
}

.accordion-trigger::after {
  content: '';
  width: 8px;
  height: 8px;
  border-right: 2px solid var(--color-text-muted);
  border-bottom: 2px solid var(--color-text-muted);
  transform: rotate(-45deg);
  transition: transform var(--transition-fast);
  flex-shrink: 0;
  margin-left: var(--space-md);
}

.accordion-item.open .accordion-trigger::after {
  transform: rotate(45deg);
}

.accordion-trigger:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: -2px;
}

.accordion-content {
  display: none;
  padding: 0 var(--space-lg) var(--space-lg);
  font-size: 0.95em;
  line-height: 1.7;
}

.accordion-item.open .accordion-content {
  display: block;
  animation: fadeIn var(--transition-fast) ease;
}


/* ============================================================
   41. MARGIN NOTES / ASIDE
   ============================================================ */

.margin-note {
  float: right;
  width: 240px;
  margin: 0 0 var(--space-lg) var(--space-xl);
  padding: var(--space-md);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  background-color: var(--color-bg-secondary);
  border-left: 3px solid var(--color-accent);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  line-height: 1.6;
}

@media (max-width: 960px) {
  .margin-note {
    float: none;
    width: 100%;
    margin: var(--space-lg) 0;
  }
}


/* ============================================================
   42. FIGURE / IMAGE CAPTIONS
   ============================================================ */

.figure {
  margin: var(--space-xl) 0;
}

.figure img {
  width: 100%;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}

.figure-caption {
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  text-align: center;
  margin-top: var(--space-sm);
  padding: 0 var(--space-lg);
}

.figure-number {
  font-weight: 700;
  color: var(--color-text-secondary);
}


/* ============================================================
   RENDERER COMPATIBILITY — classes generated by renderer.js
   ============================================================ */

/* ============================================================
    7b. CHAPTER SPUR — Collapsible Sidebar
    ============================================================ */

#chapter-spur {
  width: var(--spur-width);
  min-width: var(--spur-width);
  height: 100vh;
  position: sticky;
  top: 0;
  background-color: var(--color-bg-secondary);
  border-right: 1px solid var(--color-border);
  z-index: var(--z-nav);
  overflow-y: auto;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
  transition: width 0.25s ease, min-width 0.25s ease;
}

#chapter-spur.expanded {
  width: 260px;
  min-width: 260px;
  box-shadow: 4px 0 16px rgba(0, 0, 0, 0.08);
}

#app.hub-view #chapter-spur {
  display: none;
}

.spur-section {
  display: flex;
  flex-direction: column;
}

.spur-toggle-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 40px;
  background-color: var(--color-bg-tertiary);
  border: none;
  border-bottom: 1px solid var(--color-border);
  cursor: pointer;
  color: var(--color-text-muted);
  font-size: 14px;
  transition: background-color var(--transition-fast), color var(--transition-fast);
  flex-shrink: 0;
}

.spur-toggle-btn:hover {
  background-color: var(--color-accent-tint);
  color: var(--color-accent);
}

.spur-section-label {
  display: none;
  font-family: var(--font-heading);
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  padding: 10px 14px 4px 14px;
  border-top: 1px solid var(--color-border);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

#chapter-spur.expanded .spur-section-label {
  display: block;
}

.spur-item {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  height: 32px;
  padding: 0 0 0 13px;
  text-decoration: none;
  color: var(--color-text-muted);
  transition: all var(--transition-fast);
  position: relative;
  overflow: hidden;
  white-space: nowrap;
  flex-shrink: 0;
  gap: 8px;
}

.spur-dot {
  display: block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  border: 1.5px solid var(--spur-section-color, var(--color-text-muted));
  background: transparent;
  flex-shrink: 0;
  transition: all var(--transition-fast);
}

.spur-dot--einstieg      { --spur-section-color: #8b5cf6; }
.spur-dot--grundlagen    { --spur-section-color: #3b82f6; }
.spur-dot--prinzipien    { --spur-section-color: #6366f1; }
.spur-dot--steuerpflicht { --spur-section-color: #06b6d4; }
.spur-dot--einkuenfte    { --spur-section-color: #22c55e; }
.spur-dot--abzuege       { --spur-section-color: #f59e0b; }
.spur-dot--berechnung    { --spur-section-color: #ef4444; }
.spur-dot--tarif         { --spur-section-color: #ec4899; }
.spur-dot--praxis        { --spur-section-color: #14b8a6; }

.spur-item:hover .spur-dot {
  transform: scale(1.4);
  background-color: var(--spur-section-color, var(--color-accent));
}

.spur-item.active .spur-dot {
  width: 10px;
  height: 10px;
  background-color: #ffffff;
  border-color: #ffffff;
  box-shadow: 0 0 0 2px rgba(255,255,255,0.3);
}

.spur-item.completed .spur-dot {
  background-color: var(--spur-section-color, var(--color-callout-success));
}

.spur-label {
  display: none;
  font-family: var(--font-heading);
  font-size: 12px;
  font-weight: 500;
  color: var(--color-text-secondary);
  padding-right: 14px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  transition: color var(--transition-fast);
}

#chapter-spur.expanded .spur-label {
  display: inline;
}

#chapter-spur.expanded .spur-item {
  padding-left: 14px;
}

.spur-item:hover {
  background-color: var(--color-accent-tint);
}

.spur-item:hover .spur-label {
  color: var(--color-accent);
}

.spur-item.active {
  background-color: var(--color-accent);
}

.spur-item.active .spur-label {
  color: #ffffff;
  font-weight: 600;
}

.spur-item.completed .spur-label {
  color: var(--color-callout-success);
}

.spur-item.completed::after {
  content: '';
  position: absolute;
  top: 4px;
  left: 26px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background-color: var(--color-callout-success);
}

#chapter-spur.expanded .spur-item.completed::after {
  left: 22px;
}


/* ============================================================
    8b. HUB PAGE — Cards & Layout
    ============================================================ */

.hub {
  text-align: center;
  padding-top: var(--space-xl);
}

.hub-header {
  text-align: center;
  margin-bottom: var(--space-3xl);
}

.hub-icon {
  font-size: 48px;
  margin-bottom: var(--space-md);
  line-height: 1;
}

.hub-title {
  font-family: var(--font-heading);
  font-size: var(--font-size-4xl);
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: var(--space-md);
  line-height: 1.2;
}

.hub-description {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  max-width: 600px;
  margin: 0 auto;
  line-height: 1.75;
}

.hub-progress {
  margin-bottom: var(--space-3xl);
}

.hub-progress-label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-sm);
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.hub-progress-bar {
  width: 100%;
  max-width: 400px;
  height: 6px;
  background-color: var(--color-bg-tertiary);
  border-radius: var(--radius-full);
  overflow: hidden;
  margin: 0 auto var(--space-sm) auto;
}

.hub-progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--color-accent), var(--color-accent-hover));
  border-radius: var(--radius-full);
  transition: width 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  min-width: 0;
}

.hub-progress .progress-text {
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  display: block;
  text-align: center;
}

.hub-courses {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  max-width: 580px;
  margin: 0 auto;
  width: 100%;
}

.hub-course-card {
  display: flex;
  flex-direction: column;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  text-align: left;
  transition:
    box-shadow var(--transition-base),
    border-color var(--transition-base),
    transform var(--transition-base),
    background-color var(--transition-theme);
  cursor: pointer;
  text-decoration: none;
  color: inherit;
  position: relative;
  overflow: hidden;
}

.hub-course-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--color-accent);
  transform: translateY(-2px);
  text-decoration: none;
  color: inherit;
}

.hub-course-card:active {
  transform: translateY(0);
}

.hub-course-accent {
  height: 4px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-accent-hover));
}

.hub-course-body {
  padding: var(--space-xl);
}

.hub-course-icon {
  font-size: 36px;
  margin-bottom: var(--space-md);
  line-height: 1;
}

.hub-course-title {
  font-family: var(--font-heading);
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--space-sm);
}

.hub-course-desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin-bottom: var(--space-lg);
}

.hub-course-meta {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  font-family: var(--font-heading);
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.hub-course-meta-item {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.hub-back {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-lg);
  transition: color var(--transition-fast);
}

.hub-back:hover {
  color: var(--color-accent);
  text-decoration: none;
}

.hub-chapters {
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
  max-width: 680px;
  margin: 0 auto;
  width: 100%;
  text-align: left;
}

.hub-section {
  margin-bottom: var(--space-md);
}

.hub-section-title {
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-xs);
  border-bottom: 2px solid var(--color-accent-tint-strong);
  text-align: left;
}

.hub-card {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-md) var(--space-lg);
  text-decoration: none;
  color: inherit;
  transition:
    box-shadow var(--transition-base),
    border-color var(--transition-base),
    transform var(--transition-base),
    background-color var(--transition-theme);
  cursor: pointer;
  text-align: left;
}

.hub-card:hover {
  box-shadow: var(--shadow-sm);
  border-color: var(--color-accent);
  transform: translateX(4px);
  background-color: var(--color-surface-hover);
  text-decoration: none;
}

.hub-card.completed {
  border-left: 3px solid var(--color-callout-success);
}

.hub-card-icon {
  font-size: 1.4em;
  flex-shrink: 0;
  width: 32px;
  text-align: center;
}

.hub-card-label {
  font-family: var(--font-heading);
  font-size: var(--font-size-base);
  font-weight: 500;
  color: var(--color-text-primary);
  flex-grow: 1;
}

.hub-card-check {
  color: var(--color-callout-success);
  font-weight: 700;
  font-size: var(--font-size-lg);
  flex-shrink: 0;
}

.feature-text {
  flex: 1;
  min-width: 0;
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: 1.6;
}

.feature-text strong {
  display: block;
  font-family: var(--font-heading);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--space-xs);
  font-size: var(--font-size-base);
}

.feature-text h3 {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: var(--font-size-base);
  color: var(--color-text-primary);
  margin-bottom: var(--space-xs);
}


/* ============================================================
    16b. SLIDE NAVIGATION — Bottom Bar
    ============================================================ */

.slide-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: var(--space-sm) 0;
  width: 100%;
  max-width: var(--content-max-width);
}

.slide-nav-btn {
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 500;
  padding: var(--space-xs) var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background-color: var(--color-surface);
  color: var(--color-text-primary);
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.slide-nav-btn:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background-color: var(--color-accent-tint);
}

.slide-nav-btn:active {
  transform: scale(0.97);
}

.slide-dots {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  flex: 1;
  overflow-x: auto;
}

.slide-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--color-border);
  cursor: pointer;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.slide-dot:hover {
  background-color: var(--color-text-muted);
  transform: scale(1.3);
}

.slide-dot.active {
  background-color: var(--color-accent);
  transform: scale(1.2);
  box-shadow: 0 0 0 2px var(--color-accent-tint-strong);
}


/* ============================================================
    APPENDIX — Dark Mode Overrides
    ============================================================ */

[data-theme="dark"] .hub-card {
  background-color: var(--color-bg-secondary);
}

[data-theme="dark"] .hub-card:hover {
  background-color: var(--color-bg-tertiary);
}

[data-theme="dark"] .hub-course-card {
  background-color: var(--color-bg-secondary);
}

[data-theme="dark"] .hub-course-card:hover {
  background-color: var(--color-bg-tertiary);
  border-color: var(--color-accent);
}

[data-theme="dark"] .spur-toggle-btn {
  background-color: var(--color-bg-tertiary);
}

[data-theme="dark"] .spur-item:hover {
  background-color: rgba(129, 140, 248, 0.15);
}

[data-theme="dark"] .spur-item.active {
  box-shadow: none;
}

[data-theme="dark"] .spur-dot {
  border-color: var(--spur-section-color, var(--color-text-muted));
}

[data-theme="dark"] #chapter-spur {
  background-color: var(--color-bg-secondary);
  border-right-color: var(--color-border);
}

[data-theme="dark"] #chapter-spur.expanded {
  box-shadow: 4px 0 16px rgba(0, 0, 0, 0.3);
}

[data-theme="dark"] .slide-nav-btn {
  background-color: var(--color-bg-secondary);
  border-color: var(--color-border);
  color: var(--color-text-primary);
}

[data-theme="dark"] .slide-nav-btn:hover {
  border-color: var(--color-accent);
  background-color: rgba(129, 140, 248, 0.1);
}

[data-theme="dark"] .slide-dot {
  background-color: var(--color-border);
}

[data-theme="dark"] .slide-dot.active {
  background-color: var(--color-accent);
}

.feedback-correct {
  margin-top: var(--space-md);
  padding: var(--space-md);
  background-color: var(--color-callout-success-bg);
  border-left: 4px solid var(--color-callout-success);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  color: var(--color-text-primary);
  line-height: 1.6;
}

.feedback-wrong {
  margin-top: var(--space-md);
  padding: var(--space-md);
  background-color: var(--color-callout-danger-bg);
  border-left: 4px solid var(--color-callout-danger);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  color: var(--color-text-primary);
  line-height: 1.6;
}

.decision-option.disabled {
  pointer-events: none;
  opacity: 0.65;
}

.decision-option.correct {
  border-color: var(--color-callout-success) !important;
  background-color: var(--color-callout-success-bg) !important;
}

.decision-option.wrong {
  border-color: var(--color-callout-danger) !important;
  background-color: var(--color-callout-danger-bg) !important;
}

.decision-option.selected {
  font-weight: 600;
}

.copy-btn.copied {
  background-color: var(--color-callout-success);
  color: var(--color-text-inverse);
  border-color: var(--color-callout-success);
}

.btn-primary {
  display: inline-block;
  font-family: var(--font-heading);
  font-size: var(--font-size-base);
  font-weight: 600;
  padding: var(--space-md) var(--space-xl);
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-hover));
  color: var(--color-text-inverse);
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  text-decoration: none;
  transition: all var(--transition-base);
  text-align: center;
}

.btn-primary:hover {
  box-shadow: 0 4px 16px var(--color-accent-tint-strong);
  transform: translateY(-2px);
  text-decoration: none;
}

.btn-primary:active {
  transform: translateY(0);
  box-shadow: none;
}

/* ============================================================
    END OF STYLESHEET
    ============================================================ */