/* ==========================================================================
   BeatWritersBlock Design System
   WCAG 2.1 Level AA Compliant
   ========================================================================== */

/* ==========================================================================
   1. CSS Custom Properties (Design Tokens)
   ========================================================================== */

:root {
  /* Brand Colors - Deep Navy Palette (Scholarly/Academic) */
  --color-primary: #1e3a5f;           /* Deep navy - primary brand (10.5:1 contrast on white) */
  --color-primary-dark: #152a45;      /* Darker navy for hover states */
  --color-primary-light: #2d4a6f;     /* Lighter navy for accents */
  --color-accent: #1e3a5f;            /* Same as primary - unified brand */
  --color-accent-dark: #152a45;       /* Darker for hover */
  --color-accent-light: #2d4a6f;      /* Lighter variant */

  /* Background Colors - Warm Off-White */
  --color-background: #FAF9F6;        /* Off-white background */
  --color-background-alt: #F5F0E8;    /* Warm cream for sections */
  --color-surface: #FFFFFF;           /* Card/component backgrounds */

  /* Text Colors - High Contrast for Accessibility */
  --color-text: #1A1A1A;              /* Near-black - 17.4:1 contrast (AAA) */
  --color-text-secondary: #4A4A4A;    /* Medium gray - 8.5:1 contrast (AAA) */
  --color-text-muted: #6B6B6B;        /* Muted gray - 5.1:1 contrast (AA) */
  --color-text-on-primary: #FFFFFF;   /* White text on burgundy backgrounds */

  /* Border Colors */
  --color-border: #E0DCD4;            /* Subtle warm border */
  --color-border-strong: #C8C2B8;     /* Stronger border */

  /* Semantic Colors */
  --color-success: #27ae60;           /* Success states */
  --color-warning: #f39c12;           /* Warning states */
  --color-error: #e74c3c;             /* Error states */
  --color-info: #3498db;              /* Info states */

  /* Block Type Colors (for quiz results) */
  --color-cognitive: #9b59b6;         /* Purple for cognitive block */
  --color-physiological: #27ae60;     /* Green for physiological block */
  --color-motivational: #3498db;      /* Blue for motivational block */
  --color-behavioral: #e67e22;        /* Orange for behavioral block */
  --color-composition: #1abc9c;       /* Teal for composition block */

  /* Typography - Accessible Fonts */
  --font-sans: 'Atkinson Hyperlegible', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-serif: 'Merriweather', Georgia, 'Times New Roman', serif;
  --font-mono: 'Fira Code', 'SF Mono', Monaco, monospace;

  /* Font Sizes (fluid typography) */
  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
  --text-sm: clamp(0.875rem, 0.8rem + 0.375vw, 1rem);
  --text-base: clamp(1rem, 0.9rem + 0.5vw, 1.125rem);
  --text-lg: clamp(1.125rem, 1rem + 0.625vw, 1.25rem);
  --text-xl: clamp(1.25rem, 1.1rem + 0.75vw, 1.5rem);
  --text-2xl: clamp(1.5rem, 1.25rem + 1.25vw, 2rem);
  --text-3xl: clamp(1.875rem, 1.5rem + 1.875vw, 2.5rem);
  --text-4xl: clamp(2.25rem, 1.75rem + 2.5vw, 3rem);

  /* Line Heights */
  --leading-tight: 1.25;
  --leading-snug: 1.375;
  --leading-normal: 1.5;
  --leading-relaxed: 1.625;
  --leading-loose: 2;

  /* Font Weights */
  --font-normal: 400;
  --font-medium: 500;
  --font-semibold: 600;
  --font-bold: 700;

  /* Spacing Scale */
  --space-1: 0.25rem;   /* 4px */
  --space-2: 0.5rem;    /* 8px */
  --space-3: 0.75rem;   /* 12px */
  --space-4: 1rem;      /* 16px */
  --space-5: 1.25rem;   /* 20px */
  --space-6: 1.5rem;    /* 24px */
  --space-8: 2rem;      /* 32px */
  --space-10: 2.5rem;   /* 40px */
  --space-12: 3rem;     /* 48px */
  --space-16: 4rem;     /* 64px */
  --space-20: 5rem;     /* 80px */
  --space-24: 6rem;     /* 96px */

  /* Border Radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07), 0 2px 4px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1), 0 4px 6px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.1), 0 10px 10px rgba(0, 0, 0, 0.04);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 350ms ease;

  /* Layout */
  --container-sm: 640px;
  --container-md: 768px;
  --container-lg: 1024px;
  --container-xl: 1200px;
  --content-width: 65ch;

  /* Z-index Scale */
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-modal: 300;
  --z-tooltip: 400;
}

/* ==========================================================================
   2. CSS Reset & Base Styles
   ========================================================================== */

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

* {
  margin: 0;
  padding: 0;
}

html {
  font-size: 100%;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

/* Reduce motion for users who prefer it */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: var(--leading-normal);
  color: var(--color-text);
  background-color: var(--color-background);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ==========================================================================
   3. Accessibility Features
   ========================================================================== */

/* Skip Link - visible on focus */
.skip-link {
  position: absolute;
  top: -100%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--color-primary);
  color: white;
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-md);
  font-weight: var(--font-semibold);
  z-index: var(--z-tooltip);
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: var(--space-4);
  outline: 3px solid var(--color-accent);
  outline-offset: 2px;
}

/* Focus Styles - WCAG 2.1 AA Compliant */
:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

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

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

/* Touch Targets - Minimum 44x44px */
button,
a,
input[type="checkbox"],
input[type="radio"],
select {
  min-height: 44px;
  min-width: 44px;
}

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

/* ==========================================================================
   4. Typography
   ========================================================================== */

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-sans);
  font-weight: var(--font-bold);
  line-height: var(--leading-tight);
  color: var(--color-text);
}

h1 {
  font-size: var(--text-4xl);
  margin-bottom: var(--space-6);
}

h2 {
  font-size: var(--text-3xl);
  margin-bottom: var(--space-5);
  margin-top: var(--space-12);
}

h3 {
  font-size: var(--text-2xl);
  margin-bottom: var(--space-4);
  margin-top: var(--space-8);
}

h4 {
  font-size: var(--text-xl);
  margin-bottom: var(--space-3);
  margin-top: var(--space-6);
}

p {
  font-family: var(--font-serif);
  font-size: var(--text-base);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-4);
  max-width: var(--content-width);
}

a {
  color: var(--color-primary);
  text-decoration: underline;
  text-underline-offset: 2px;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-dark);
}

/* ==========================================================================
   5. Layout Components
   ========================================================================== */

.container {
  width: 100%;
  max-width: var(--container-xl);
  margin: 0 auto;
  padding: 0 var(--space-4);
}

@media (min-width: 768px) {
  .container {
    padding: 0 var(--space-8);
  }
}

main {
  min-height: calc(100vh - 200px);
}

/* ==========================================================================
   6. Navigation
   ========================================================================== */

.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) 0;
  gap: var(--space-6);
}

.site-logo {
  font-size: var(--text-xl);
  font-weight: var(--font-bold);
  color: var(--color-primary);
  text-decoration: none;
}

.site-logo:hover {
  color: var(--color-primary-dark);
}

.main-nav {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

.nav-link {
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-text);
  text-decoration: none;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.nav-link:hover {
  color: var(--color-primary);
  background: rgba(26, 83, 92, 0.05);
}

.nav-link.active {
  color: var(--color-primary);
  background: rgba(26, 83, 92, 0.1);
}

/* ==========================================================================
   7. Buttons
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  text-decoration: none;
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  min-height: 44px;
  min-width: 44px;
}

.btn-primary {
  background: var(--color-accent);
  color: white;
  border-color: var(--color-accent);
}

.btn-primary:hover {
  background: var(--color-accent-dark);
  border-color: var(--color-accent-dark);
  color: white;
}

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

.btn-secondary:hover {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  color: white;
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn-outline:hover {
  background: var(--color-primary);
  color: white;
}

.btn-lg {
  padding: var(--space-4) var(--space-8);
  font-size: var(--text-base);
}

/* ==========================================================================
   8. Cards
   ========================================================================== */

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
}

.card:hover {
  box-shadow: var(--shadow-md);
}

.card-link {
  text-decoration: none;
  color: inherit;
  display: block;
}

.card-title {
  font-size: var(--text-xl);
  margin-bottom: var(--space-2);
}

.card-description {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

/* ==========================================================================
   9. Quiz Styles (WCAG 2.1 AA Compliant)
   ========================================================================== */

.quiz-container {
  max-width: 700px;
  margin: 0 auto;
  padding: var(--space-8);
}

.quiz-progress {
  margin-bottom: var(--space-6);
}

.quiz-progress-bar {
  height: 8px;
  background: var(--color-border);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.quiz-progress-fill {
  height: 100%;
  background: var(--color-primary);
  border-radius: var(--radius-full);
  transition: width var(--transition-normal);
}

.quiz-progress-text {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-top: var(--space-2);
}

/* Quiz Question */
.quiz-question {
  margin-bottom: var(--space-8);
}

.quiz-question fieldset {
  border: none;
  padding: 0;
}

.quiz-question legend {
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  color: var(--color-text);
  margin-bottom: var(--space-6);
  line-height: var(--leading-snug);
}

/* Quiz Answers */
.quiz-answers {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.quiz-answer {
  position: relative;
}

.quiz-answer input[type="radio"] {
  position: absolute;
  opacity: 0;
  width: 100%;
  height: 100%;
  cursor: pointer;
}

.quiz-answer label {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-4) var(--space-5);
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-family: var(--font-sans);
  font-size: var(--text-base);
  min-height: 60px;
}

.quiz-answer label::before {
  content: '';
  width: 24px;
  height: 24px;
  border: 2px solid var(--color-border-dark);
  border-radius: 50%;
  flex-shrink: 0;
  transition: all var(--transition-fast);
}

.quiz-answer input[type="radio"]:hover + label,
.quiz-answer label:hover {
  border-color: var(--color-primary-light);
  background: rgba(26, 83, 92, 0.02);
}

.quiz-answer input[type="radio"]:focus + label {
  outline: 3px solid var(--color-accent);
  outline-offset: 2px;
}

.quiz-answer input[type="radio"]:checked + label {
  border-color: var(--color-primary);
  background: rgba(26, 83, 92, 0.05);
}

.quiz-answer input[type="radio"]:checked + label::before {
  border-color: var(--color-primary);
  background: var(--color-primary);
  box-shadow: inset 0 0 0 4px white;
}

/* Quiz Error State */
.quiz-error {
  color: var(--color-error);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  margin-top: var(--space-4);
  padding: var(--space-3) var(--space-4);
  background: rgba(231, 76, 60, 0.1);
  border-radius: var(--radius-md);
  display: none;
}

.quiz-error[aria-live] {
  display: block;
}

.quiz-error.visible {
  display: block;
}

/* Quiz Navigation */
.quiz-nav {
  display: flex;
  justify-content: space-between;
  gap: var(--space-4);
  margin-top: var(--space-8);
}

/* Quiz Results */
.quiz-result {
  text-align: center;
  padding: var(--space-8);
}

.quiz-result-icon {
  width: 80px;
  height: 80px;
  margin: 0 auto var(--space-6);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 40px;
}

.quiz-result-title {
  font-size: var(--text-3xl);
  margin-bottom: var(--space-4);
}

.quiz-result-percentage {
  font-size: var(--text-xl);
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
}

.quiz-result-description {
  font-size: var(--text-lg);
  max-width: 50ch;
  margin: 0 auto var(--space-8);
}

/* Block Type Specific Colors */
.result-cognitive .quiz-result-icon { background: rgba(155, 89, 182, 0.15); }
.result-physiological .quiz-result-icon { background: rgba(39, 174, 96, 0.15); }
.result-motivational .quiz-result-icon { background: rgba(52, 152, 219, 0.15); }
.result-behavioral .quiz-result-icon { background: rgba(230, 126, 34, 0.15); }
.result-composition .quiz-result-icon { background: rgba(26, 188, 156, 0.15); }

/* Quiz Tips */
.quiz-tips {
  text-align: left;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  margin-bottom: var(--space-8);
}

.quiz-tips h3 {
  font-size: var(--text-lg);
  margin-bottom: var(--space-4);
  margin-top: 0;
}

.quiz-tips ul {
  padding-left: var(--space-5);
}

.quiz-tips li {
  margin-bottom: var(--space-2);
  font-family: var(--font-serif);
}

/* Quiz Recommended Articles */
.quiz-articles {
  text-align: left;
}

.quiz-articles h3 {
  font-size: var(--text-lg);
  margin-bottom: var(--space-4);
  margin-top: 0;
}

.quiz-article-card {
  display: block;
  padding: var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-3);
  text-decoration: none;
  transition: all var(--transition-fast);
}

.quiz-article-card:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
}

.quiz-article-title {
  font-weight: var(--font-semibold);
  color: var(--color-primary);
  margin-bottom: var(--space-1);
}

.quiz-article-desc {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

/* ==========================================================================
   10. Footer
   ========================================================================== */

.site-footer {
  background: var(--color-primary);
  color: white;
  padding: var(--space-12) 0 var(--space-8);
  margin-top: var(--space-16);
}

.footer-inner {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-8);
}

.footer-section h4 {
  color: white;
  font-size: var(--text-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-4);
  margin-top: 0;
}

.footer-section a {
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  display: block;
  padding: var(--space-1) 0;
  transition: color var(--transition-fast);
}

.footer-section a:hover {
  color: white;
}

.footer-bottom {
  margin-top: var(--space-8);
  padding-top: var(--space-6);
  border-top: 1px solid rgba(255, 255, 255, 0.2);
  font-size: var(--text-sm);
  color: rgba(255, 255, 255, 0.7);
}

/* ==========================================================================
   11. Utility Classes
   ========================================================================== */

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

.mt-4 { margin-top: var(--space-4); }
.mt-8 { margin-top: var(--space-8); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-8 { margin-bottom: var(--space-8); }

.hidden { display: none; }
.visible { display: block; }

/* ==========================================================================
   12. Mobile Menu
   ========================================================================== */

/* Mobile Menu Toggle Button */
.mobile-menu-toggle {
  display: none;
  background: transparent;
  border: none;
  padding: var(--space-2);
  cursor: pointer;
  position: relative;
  z-index: calc(var(--z-sticky) + 1);
  min-height: 44px;
  min-width: 44px;
}

.hamburger-icon {
  display: block;
  width: 24px;
  height: 20px;
  position: relative;
}

.hamburger-icon span {
  display: block;
  position: absolute;
  height: 3px;
  width: 100%;
  background: var(--color-text);
  border-radius: 3px;
  opacity: 1;
  left: 0;
  transform: rotate(0deg);
  transition: all var(--transition-fast);
}

.hamburger-icon span:nth-child(1) { top: 0; }
.hamburger-icon span:nth-child(2) { top: 8px; }
.hamburger-icon span:nth-child(3) { top: 16px; }

/* Animated X when open */
.mobile-menu-toggle[aria-expanded="true"] .hamburger-icon span:nth-child(1) {
  top: 8px;
  transform: rotate(135deg);
}

.mobile-menu-toggle[aria-expanded="true"] .hamburger-icon span:nth-child(2) {
  opacity: 0;
}

.mobile-menu-toggle[aria-expanded="true"] .hamburger-icon span:nth-child(3) {
  top: 8px;
  transform: rotate(-135deg);
}

/* ==========================================================================
   13. Responsive Adjustments
   ========================================================================== */

/* ==========================================================================
   14. Article Enhancement Components
   ========================================================================== */

/* --- Quick Takeaways Box --- */
.quick-takeaways {
  background: var(--color-surface);
  border: 2px solid var(--color-primary);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  margin-bottom: var(--space-8);
}

.quick-takeaways-header {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-sans);
  font-weight: var(--font-bold);
  font-size: var(--text-sm);
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-4);
}

.quick-takeaways-header::before {
  content: '⚡';
}

.quick-takeaways ul {
  list-style: none;
  padding: 0;
  margin: 0 0 var(--space-4) 0;
}

.quick-takeaways li {
  position: relative;
  padding-left: var(--space-5);
  margin-bottom: var(--space-2);
  font-family: var(--font-serif);
  font-size: var(--text-base);
  line-height: var(--leading-relaxed);
}

.quick-takeaways li::before {
  content: '•';
  position: absolute;
  left: 0;
  color: var(--color-primary);
  font-weight: var(--font-bold);
}

.quick-takeaways-meta {
  display: flex;
  gap: var(--space-4);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  padding-top: var(--space-3);
  border-top: 1px solid var(--color-border);
}

/* --- Block Type Tags --- */
.block-type-tag {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  text-transform: uppercase;
  letter-spacing: 0.03em;
  margin-bottom: var(--space-4);
}

.block-type-tag--cognitive {
  background: rgba(155, 89, 182, 0.15);
  color: #7d3c98;
}

.block-type-tag--physiological {
  background: rgba(39, 174, 96, 0.15);
  color: #1e8449;
}

.block-type-tag--motivational {
  background: rgba(52, 152, 219, 0.15);
  color: #2471a3;
}

.block-type-tag--behavioral {
  background: rgba(230, 126, 34, 0.15);
  color: #b9770e;
}

.block-type-tag--composition {
  background: rgba(26, 188, 156, 0.15);
  color: #148f77;
}

/* --- Action Steps Callout --- */
.action-steps {
  background: var(--color-background-alt);
  border-left: 4px solid var(--color-primary);
  border-radius: 0 var(--radius-lg) var(--radius-lg) 0;
  padding: var(--space-5);
  margin: var(--space-6) 0;
}

.action-steps-header {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-sans);
  font-weight: var(--font-bold);
  font-size: var(--text-sm);
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-4);
}

.action-steps ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.action-steps li {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
  font-family: var(--font-serif);
  font-size: var(--text-base);
  line-height: var(--leading-relaxed);
}

.action-steps li::before {
  content: '☐';
  flex-shrink: 0;
  color: var(--color-primary);
  font-size: var(--text-lg);
}

.action-steps li:last-child {
  margin-bottom: 0;
}

/* --- Research Citation Box --- */
.research-box {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  margin: var(--space-6) 0;
}

.research-box-header {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-sans);
  font-weight: var(--font-bold);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-3);
}

.research-box-header::before {
  content: '📚';
}

.research-box-study {
  font-family: var(--font-sans);
  font-weight: var(--font-semibold);
  font-size: var(--text-base);
  color: var(--color-text);
  margin-bottom: var(--space-2);
}

.research-box-finding {
  font-family: var(--font-serif);
  font-size: var(--text-base);
  line-height: var(--leading-relaxed);
  color: var(--color-text);
  margin-bottom: var(--space-2);
}

.research-box-sample {
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

/* --- Related Articles Section --- */
.related-articles {
  margin-top: var(--space-12);
  padding-top: var(--space-8);
  border-top: 1px solid var(--color-border);
}

.related-articles-header {
  font-family: var(--font-sans);
  font-weight: var(--font-bold);
  font-size: var(--text-lg);
  color: var(--color-text);
  text-transform: uppercase;
  letter-spacing: 0.03em;
  margin-bottom: var(--space-5);
}

.related-articles-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.related-article-link {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: all var(--transition-fast);
}

.related-article-link:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-sm);
}

.related-article-link::before {
  content: '├──';
  font-family: var(--font-mono);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

.related-article-link:last-child::before {
  content: '└──';
}

.related-article-link span {
  color: var(--color-primary);
  font-family: var(--font-sans);
  font-weight: var(--font-medium);
}

.related-article-link--cta {
  background: var(--color-primary);
  border-color: var(--color-primary);
}

.related-article-link--cta span {
  color: white;
}

.related-article-link--cta::before {
  color: rgba(255, 255, 255, 0.7);
}

.related-article-link--cta:hover {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
}

/* --- Reading Progress Bar --- */
.reading-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: transparent;
  z-index: calc(var(--z-sticky) + 10);
}

.reading-progress-bar {
  height: 100%;
  background: var(--color-primary);
  width: 0%;
  transition: width 100ms ease-out;
}

/* --- Table of Contents --- */
.article-toc {
  background: var(--color-background-alt);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  margin-bottom: var(--space-8);
}

.article-toc-header {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-sans);
  font-weight: var(--font-bold);
  font-size: var(--text-sm);
  color: var(--color-text);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-4);
}

.article-toc-list {
  list-style: none;
  padding: 0;
  margin: 0;
  counter-reset: toc-counter;
}

.article-toc-list li {
  counter-increment: toc-counter;
  margin-bottom: var(--space-2);
}

.article-toc-list a {
  display: flex;
  align-items: baseline;
  gap: var(--space-3);
  color: var(--color-text);
  text-decoration: none;
  font-family: var(--font-sans);
  font-size: var(--text-base);
  padding: var(--space-2) 0;
  border-bottom: 1px solid transparent;
  transition: all var(--transition-fast);
}

.article-toc-list a::before {
  content: counter(toc-counter) '.';
  color: var(--color-primary);
  font-weight: var(--font-semibold);
  min-width: 1.5em;
}

.article-toc-list a:hover {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

/* --- Article Meta --- */
.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
}

.article-meta-item {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

/* --- Topic Tag --- */
.topic-tag {
  display: inline-flex;
  align-items: center;
  padding: var(--space-1) var(--space-3);
  background: var(--color-background-alt);
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: var(--text-xs);
  font-weight: var(--font-medium);
  color: var(--color-text-secondary);
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  transition: all var(--transition-fast);
}

.topic-tag:hover {
  background: var(--color-primary);
  color: white;
}

/* --- Article Figures --- */
.article-figure {
  margin: var(--space-8) 0;
  padding: 0;
  max-width: 100%;
}

.article-figure img {
  display: block;
  max-width: 100%;
  height: auto;
  width: auto;
  margin: 0 auto;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
}

.article-figure figcaption {
  margin-top: var(--space-3);
  padding: 0 var(--space-4);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  text-align: center;
  line-height: var(--leading-relaxed);
}

/* Cover images in articles */
.article-cover {
  width: 100%;
  margin-bottom: var(--space-8);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.article-cover img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

/* Ensure figures don't overflow on mobile */
figure {
  margin: var(--space-6) 0;
  max-width: 100%;
}

figure img {
  max-width: 100%;
  height: auto;
}

/* ==========================================================================
   15. Responsive Adjustments
   ========================================================================== */

@media (max-width: 768px) {
  /* Show mobile menu toggle */
  .mobile-menu-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
  }

  /* Mobile navigation menu */
  .main-nav {
    display: none;
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-lg);
    padding: var(--space-4);
    flex-direction: column;
    gap: 0;
    z-index: var(--z-sticky);
  }

  .main-nav[aria-hidden="false"] {
    display: flex;
  }

  .main-nav .nav-link {
    display: block;
    width: 100%;
    padding: var(--space-4);
    border-bottom: 1px solid var(--color-border);
    border-radius: 0;
    text-align: left;
  }

  .main-nav .nav-link:last-of-type {
    border-bottom: none;
  }

  .main-nav .btn {
    margin-top: var(--space-4);
    width: 100%;
    text-align: center;
  }

  /* Quiz adjustments */
  .quiz-container {
    padding: var(--space-4);
  }

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

  .quiz-nav {
    flex-direction: column;
  }

  .quiz-nav .btn {
    width: 100%;
  }

  /* Footer link touch targets */
  .footer-section a {
    padding: var(--space-3) 0;
    min-height: 44px;
    display: flex;
    align-items: center;
  }

  /* Article enhancement responsive adjustments */
  .quick-takeaways {
    padding: var(--space-4);
  }

  .quick-takeaways-meta {
    flex-direction: column;
    gap: var(--space-2);
  }

  .article-meta {
    flex-direction: column;
    gap: var(--space-2);
  }

  .action-steps {
    padding: var(--space-4);
  }

  .research-box {
    padding: var(--space-4);
  }

  .related-article-link {
    padding: var(--space-4);
  }

  .article-toc {
    padding: var(--space-4);
  }

  /* Figure responsive adjustments */
  .article-figure {
    margin: var(--space-6) calc(-1 * var(--space-4));
  }

  .article-figure img {
    border-radius: 0;
  }

  .article-figure figcaption {
    padding: 0 var(--space-4);
    font-size: var(--text-xs);
  }

  .article-cover {
    margin-left: calc(-1 * var(--space-4));
    margin-right: calc(-1 * var(--space-4));
    border-radius: 0;
  }

  .share-buttons {
    flex-direction: column;
  }

  .nav-share-dropdown {
    right: 0;
    left: auto;
  }
}

/* ==========================================================================
   17. Share Components
   ========================================================================== */

/* Article Share Section */
.article-share {
  margin-top: var(--space-8);
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-border);
}

.article-share-header {
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-3);
}

.share-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.share-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  text-decoration: none;
  cursor: pointer;
  transition: all 0.2s ease;
}

.share-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: var(--color-background);
}

.share-btn.copied {
  border-color: var(--color-success);
  color: var(--color-success);
}

.share-btn svg {
  flex-shrink: 0;
}

/* Nav Share Button */
.nav-share-wrapper {
  position: relative;
}

.nav-share-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all 0.2s ease;
}

.nav-share-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.nav-share-dropdown {
  display: none;
  position: absolute;
  top: 100%;
  right: 0;
  margin-top: var(--space-2);
  padding: var(--space-2);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  min-width: 160px;
  z-index: var(--z-dropdown);
}

.nav-share-dropdown.active {
  display: block;
}

.nav-share-dropdown a,
.nav-share-dropdown button {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  width: 100%;
  padding: var(--space-2) var(--space-3);
  background: transparent;
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  color: var(--color-text);
  text-decoration: none;
  cursor: pointer;
  text-align: left;
}

.nav-share-dropdown a:hover,
.nav-share-dropdown button:hover {
  background: var(--color-background-alt);
}