/* ============================================
   RestCalc — Sleep Smarter. Wake Refreshed.
   Modern, calming, peaceful design system
   ============================================ */

/* Google Fonts */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Nunito:wght@400;600;700;800&display=swap');
@import url('https://fonts.cdnfonts.com/css/opendyslexic');

/* ============================================
   CSS Custom Properties (Design Tokens)
   ============================================ */
:root {
  /* Primary palette */
  --primary: #7c83db;
  --primary-light: #a29bfe;
  --primary-dark: #5a5fb8;
  --primary-bg: rgba(124, 131, 219, 0.08);
  --primary-bg-strong: rgba(124, 131, 219, 0.15);

  /* Accent */
  --accent: #f9ca24;
  --accent-light: #ffeaa7;

  /* Semantic colors */
  --success: #55efc4;
  --success-bg: rgba(85, 239, 196, 0.15);
  --warning: #ff7675;
  --warning-bg: rgba(255, 118, 117, 0.15);
  --info: #74b9ff;

  /* Background & surface */
  --bg: #ffffff;
  --bg-gradient: linear-gradient(135deg, #f5f3ff 0%, #ffffff 100%);
  --surface: #ffffff;
  --surface-raised: #ffffff;
  --surface-border: rgba(124, 131, 219, 0.12);

  /* Text */
  --text: #2d3436;
  --text-secondary: #636e72;
  --text-muted: #95a5a6;

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(124, 131, 219, 0.08);
  --shadow-md: 0 4px 15px rgba(124, 131, 219, 0.15);
  --shadow-lg: 0 8px 30px rgba(124, 131, 219, 0.2);
  --shadow-hover: 0 6px 20px rgba(124, 131, 219, 0.22);

  /* Layout */
  --max-width: 800px;
  --max-width-wide: 1200px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 50%;

  /* Typography */
  --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-heading: 'Nunito', 'Inter', sans-serif;

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
  --transition-slow: 0.4s ease;
}

/* ============================================
   Dark Mode
   ============================================ */
[data-theme="dark"] {
  --bg: #1a1a2e;
  --bg-gradient: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
  --surface: #16213e;
  --surface-raised: #1e2a4a;
  --surface-border: rgba(162, 155, 254, 0.15);
  --text: #e8e8ff;
  --text-secondary: #a29bfe;
  --text-muted: #8e8eb8;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 15px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.5);
  --shadow-hover: 0 6px 20px rgba(0, 0, 0, 0.45);
  --primary-bg: rgba(124, 131, 219, 0.15);
  --primary-bg-strong: rgba(124, 131, 219, 0.25);
  --success-bg: rgba(85, 239, 196, 0.2);
  --warning-bg: rgba(255, 118, 117, 0.2);
}

/* ============================================
   Reset & Base
   ============================================ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-primary);
  color: var(--text);
  background: var(--bg-gradient);
  min-height: 100vh;
  line-height: 1.7;
  font-size: 16px;
  transition: background var(--transition-slow), color var(--transition-slow);
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--primary); text-decoration: none; transition: color var(--transition-fast); }
a:hover { color: var(--primary-dark); }

/* ============================================
   Header
   ============================================ */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--surface-border);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  background: rgba(255, 255, 255, 0.85);
  transition: background var(--transition-slow), border-color var(--transition-slow);
}

[data-theme="dark"] .site-header {
  background: rgba(26, 26, 46, 0.85);
}

.header-inner {
  max-width: var(--max-width-wide);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 4px;
  font-family: var(--font-heading);
  font-size: 1.5rem;
  text-decoration: none;
  color: var(--text);
}

.logo-icon {
  width: 32px;
  height: 32px;
  margin-right: 4px;
}

.logo .logo-rest { font-weight: 400; }
.logo .logo-calc { font-weight: 800; color: var(--primary); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
}

.nav-links a {
  padding: 8px 14px;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--primary);
  background: var(--primary-bg);
}

.theme-toggle {
  background: var(--primary-bg);
  border: none;
  border-radius: var(--radius-full);
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  margin-left: 8px;
  flex-shrink: 0;
}

.theme-toggle:hover {
  background: var(--primary-bg-strong);
  transform: scale(1.05);
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
  fill: var(--primary);
}

/* Mobile menu */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.menu-toggle svg {
  width: 24px;
  height: 24px;
  fill: var(--text);
}

@media (max-width: 768px) {
  .menu-toggle { display: block; }
  .nav-links {
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--surface-border);
    flex-direction: column;
    padding: 16px 24px;
    gap: 4px;
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: all var(--transition-normal);
    z-index: 99;
  }
  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: all;
  }
  .nav-links a {
    display: block;
    padding: 12px 16px;
    font-size: 1rem;
  }
  .header-inner { padding: 0 16px; }
}

/* ============================================
   Main Content
   ============================================ */
.main-content {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 32px 24px 80px;
}

.page-title {
  font-family: var(--font-heading);
  font-size: 2rem;
  font-weight: 800;
  text-align: center;
  margin-bottom: 8px;
  color: var(--text);
}

.page-subtitle {
  text-align: center;
  color: var(--text-secondary);
  font-size: 1.05rem;
  margin-bottom: 32px;
  line-height: 1.6;
}

/* ============================================
   Cards
   ============================================ */
.card {
  background: var(--surface);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
  margin-bottom: 24px;
}

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

.card-title {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text);
}

.card-text {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* ============================================
   Calculator Container
   ============================================ */
.calc-container {
  background: var(--surface);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-xl);
  padding: 36px 32px;
  box-shadow: var(--shadow-md);
  margin-bottom: 32px;
}

/* Mode toggle */
.mode-toggle {
  display: flex;
  background: var(--primary-bg);
  border-radius: var(--radius-md);
  padding: 4px;
  margin-bottom: 28px;
}

.mode-btn {
  flex: 1;
  padding: 12px 16px;
  border: none;
  background: transparent;
  border-radius: var(--radius-sm);
  font-family: var(--font-primary);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.mode-btn.active {
  background: var(--surface);
  color: var(--primary);
  box-shadow: var(--shadow-sm);
  font-weight: 600;
}

/* ============================================
   Form Elements
   ============================================ */
.form-group {
  margin-bottom: 20px;
}

.form-label {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text);
  margin-bottom: 8px;
}

.form-hint {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.time-input-group {
  display: flex;
  gap: 12px;
  align-items: center;
}

.time-input {
  width: 100%;
  padding: 14px 18px;
  border: 2px solid var(--surface-border);
  border-radius: var(--radius-md);
  font-family: var(--font-primary);
  font-size: 1.1rem;
  color: var(--text);
  background: var(--bg);
  transition: all var(--transition-fast);
  -webkit-appearance: none;
}

.time-input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-bg-strong);
}

select.time-input {
  cursor: pointer;
}

/* Age selector */
.age-selector {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.age-option {
  padding: 10px 16px;
  border: 2px solid var(--surface-border);
  border-radius: var(--radius-md);
  background: var(--bg);
  font-family: var(--font-primary);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-align: center;
}

.age-option:hover {
  border-color: var(--primary-light);
  color: var(--primary);
}

.age-option.active {
  border-color: var(--primary);
  background: var(--primary-bg);
  color: var(--primary);
  font-weight: 600;
}

/* Number input with +/- buttons */
.number-input-group {
  display: flex;
  align-items: center;
  gap: 0;
}

.number-input-group button {
  width: 48px;
  height: 48px;
  border: 2px solid var(--surface-border);
  background: var(--primary-bg);
  color: var(--primary);
  font-size: 1.3rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
}

.number-input-group button:first-child {
  border-radius: var(--radius-md) 0 0 var(--radius-md);
}

.number-input-group button:last-child {
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.number-input-group button:hover {
  background: var(--primary);
  color: #fff;
}

.number-input-group input {
  width: 80px;
  height: 48px;
  border: 2px solid var(--surface-border);
  border-left: none;
  border-right: none;
  text-align: center;
  font-family: var(--font-primary);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text);
  background: var(--bg);
}

/* ============================================
   Results
   ============================================ */
.results {
  display: none;
  margin-top: 28px;
  padding-top: 28px;
  border-top: 2px solid var(--surface-border);
}

.results.visible {
  display: block;
  animation: fadeInUp 0.4s ease;
}

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

.results-title {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 20px;
  color: var(--text);
}

/* Wake time results */
.wake-times {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 12px;
  margin-bottom: 24px;
}

.wake-time-card {
  background: var(--primary-bg);
  border: 2px solid var(--surface-border);
  border-radius: var(--radius-lg);
  padding: 20px 16px;
  text-align: center;
  cursor: default;
  transition: all var(--transition-fast);
}

.wake-time-card:hover {
  border-color: var(--primary-light);
  transform: translateY(-2px);
}

.wake-time-card.optimal {
  border-color: var(--success);
  background: var(--success-bg);
}

.wake-time-card .cycles {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
  margin-bottom: 4px;
}

.wake-time-card .time {
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--primary-dark);
}

[data-theme="dark"] .wake-time-card .time {
  color: var(--primary-light);
}

.wake-time-card.optimal .time {
  color: #00b894;
}

.wake-time-card .hours {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-top: 2px;
}

.wake-time-card .label {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 4px;
  font-style: italic;
}

/* Sleep quality */
.quality-indicator {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px;
  background: var(--primary-bg);
  border-radius: var(--radius-md);
  margin-bottom: 24px;
}

.quality-dot {
  width: 14px;
  height: 14px;
  border-radius: var(--radius-full);
  flex-shrink: 0;
}

.quality-dot.good { background: var(--success); }
.quality-dot.ok { background: var(--accent); }
.quality-dot.poor { background: var(--warning); }

.quality-text {
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.quality-text strong {
  color: var(--text);
}

/* ============================================
   Sleep Cycle Visualization
   ============================================ */
.sleep-cycle-viz {
  margin: 24px 0;
}

.sleep-cycle-viz .viz-title {
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text);
}

.sleep-cycle-viz svg {
  width: 100%;
  height: auto;
}

/* ============================================
   Share Button
   ============================================ */
.share-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: var(--radius-md);
  font-family: var(--font-primary);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.share-btn:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.share-btn svg {
  width: 18px;
  height: 18px;
  fill: #fff;
}

/* ============================================
   Quick Tips
   ============================================ */
.tips-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin: 24px 0;
}

.tip-card {
  background: var(--surface);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-lg);
  padding: 20px;
  display: flex;
  gap: 14px;
  transition: all var(--transition-normal);
}

.tip-card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
}

.tip-icon {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  background: var(--primary-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.tip-icon svg {
  width: 22px;
  height: 22px;
  fill: var(--primary);
}

.tip-card h4 {
  font-family: var(--font-heading);
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.tip-card p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* ============================================
   Content Sections
   ============================================ */
.content-section {
  margin-bottom: 48px;
}

.content-section h2 {
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: 700;
  margin-bottom: 20px;
  color: var(--text);
}

.content-section h3 {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 600;
  margin: 24px 0 12px;
  color: var(--text);
}

.content-section p {
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 16px;
}

.content-section ul {
  color: var(--text-secondary);
  line-height: 1.8;
  padding-left: 24px;
  margin-bottom: 16px;
}

.content-section li {
  margin-bottom: 6px;
}

/* Table */
.data-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  background: var(--surface);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  margin: 20px 0;
}

.data-table th,
.data-table td {
  padding: 14px 18px;
  text-align: left;
  border-bottom: 1px solid var(--surface-border);
}

.data-table th {
  background: var(--primary-bg);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--text);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.data-table td {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.data-table tr:last-child td {
  border-bottom: none;
}

/* FAQ */
.faq-item {
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-md);
  margin-bottom: 12px;
  overflow: hidden;
  transition: all var(--transition-fast);
}

.faq-item:hover {
  border-color: var(--primary-light);
}

.faq-question {
  width: 100%;
  padding: 18px 20px;
  background: var(--surface);
  border: none;
  text-align: left;
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background var(--transition-fast);
}

.faq-question:hover {
  background: var(--primary-bg);
}

.faq-question .faq-chevron {
  width: 20px;
  height: 20px;
  fill: var(--text-muted);
  transition: transform var(--transition-fast);
  flex-shrink: 0;
}

.faq-item.open .faq-chevron {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-normal);
}

.faq-answer-inner {
  padding: 0 20px 18px;
  color: var(--text-secondary);
  line-height: 1.7;
  font-size: 0.95rem;
}

/* Internal links grid */
.internal-links {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
  margin: 24px 0;
}

.internal-link-card {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 20px;
  background: var(--surface);
  border: 2px solid var(--surface-border);
  border-radius: var(--radius-lg);
  text-decoration: none;
  color: var(--text);
  transition: all var(--transition-normal);
}

.internal-link-card:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  color: var(--text);
}

.internal-link-card .link-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: var(--primary-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.internal-link-card .link-icon svg {
  width: 24px;
  height: 24px;
  fill: var(--primary);
}

.internal-link-card h4 {
  font-family: var(--font-heading);
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 2px;
}

.internal-link-card p {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin: 0;
}

/* ============================================
   Caffeine Calculator Specifics
   ============================================ */
.caffeine-presets {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 16px;
}

.preset-btn {
  padding: 8px 14px;
  border: 2px solid var(--surface-border);
  border-radius: var(--radius-md);
  background: var(--bg);
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-family: var(--font-primary);
}

.preset-btn:hover {
  border-color: var(--primary-light);
  color: var(--primary);
}

.preset-btn.active {
  border-color: var(--primary);
  background: var(--primary-bg);
  color: var(--primary);
}

.preset-btn .preset-mg {
  font-size: 0.72rem;
  color: var(--text-muted);
  display: block;
}

.caffeine-chart-container {
  margin: 24px 0;
  background: var(--surface);
  border-radius: var(--radius-lg);
  padding: 24px;
  border: 1px solid var(--surface-border);
}

.caffeine-chart-container svg {
  width: 100%;
  height: auto;
}

/* ============================================
   Sleep Debt Calculator Specifics
   ============================================ */
.week-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 8px;
  margin: 20px 0;
}

@media (max-width: 600px) {
  .week-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

.day-input {
  background: var(--surface);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-md);
  padding: 12px 8px;
  text-align: center;
}

.day-input label {
  display: block;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.day-input input {
  width: 100%;
  padding: 8px;
  border: 2px solid var(--surface-border);
  border-radius: var(--radius-sm);
  font-family: var(--font-primary);
  font-size: 1.1rem;
  font-weight: 600;
  text-align: center;
  color: var(--text);
  background: var(--bg);
  transition: all var(--transition-fast);
}

.day-input input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-bg-strong);
}

/* Debt bar chart */
.debt-chart {
  margin: 24px 0;
}

.debt-bar-row {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 8px;
}

.debt-bar-label {
  width: 40px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
  text-align: right;
  flex-shrink: 0;
}

.debt-bar-track {
  flex: 1;
  height: 28px;
  background: var(--primary-bg);
  border-radius: var(--radius-sm);
  position: relative;
  overflow: hidden;
}

.debt-bar-fill {
  height: 100%;
  border-radius: var(--radius-sm);
  transition: width var(--transition-slow);
  min-width: 2px;
}

.debt-bar-fill.good { background: var(--success); }
.debt-bar-fill.ok { background: var(--accent); }
.debt-bar-fill.poor { background: var(--warning); }

.debt-bar-value {
  width: 50px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  flex-shrink: 0;
}

/* Health impact */
.impact-card {
  padding: 24px;
  border-radius: var(--radius-lg);
  text-align: center;
  margin: 24px 0;
}

.impact-card.good {
  background: var(--success-bg);
  border: 2px solid var(--success);
}

.impact-card.moderate {
  background: rgba(249, 202, 36, 0.15);
  border: 2px solid var(--accent);
}

.impact-card.high {
  background: var(--warning-bg);
  border: 2px solid var(--warning);
}

.impact-card .impact-icon {
  font-size: 2.5rem;
  margin-bottom: 8px;
}

.impact-card .impact-level {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.impact-card .impact-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* ============================================
   Nap Calculator Specifics
   ============================================ */
.nap-options {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 12px;
  margin: 20px 0;
}

.nap-option {
  background: var(--surface);
  border: 2px solid var(--surface-border);
  border-radius: var(--radius-lg);
  padding: 20px;
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.nap-option:hover {
  border-color: var(--primary-light);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

.nap-option.selected {
  border-color: var(--primary);
  background: var(--primary-bg);
}

.nap-option .duration {
  font-family: var(--font-heading);
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--primary);
}

.nap-option .duration-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.nap-option .nap-type {
  font-family: var(--font-heading);
  font-size: 0.95rem;
  font-weight: 600;
  margin: 8px 0 4px;
}

.nap-option .nap-desc {
  font-size: 0.8rem;
  color: var(--text-secondary);
  line-height: 1.4;
}

.alertness-meter {
  margin: 20px 0;
  padding: 20px;
  background: var(--primary-bg);
  border-radius: var(--radius-lg);
}

.alertness-bar {
  height: 12px;
  background: var(--surface-border);
  border-radius: 6px;
  overflow: hidden;
  margin: 8px 0;
}

.alertness-fill {
  height: 100%;
  border-radius: 6px;
  transition: width var(--transition-slow), background var(--transition-slow);
}

.alertness-labels {
  display: flex;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ============================================
   Mattress Cards
   ============================================ */
.mattress-grid {
  display: grid;
  gap: 24px;
  margin: 24px 0;
}

.mattress-card {
  background: var(--surface);
  border: 2px solid var(--surface-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  transition: all var(--transition-normal);
}

.mattress-card:hover {
  border-color: var(--primary-light);
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.mattress-card-inner {
  display: flex;
  gap: 24px;
  padding: 24px;
}

@media (max-width: 600px) {
  .mattress-card-inner {
    flex-direction: column;
    gap: 16px;
  }
}

.mattress-img {
  width: 180px;
  height: 140px;
  background: var(--primary-bg);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.mattress-img svg {
  width: 64px;
  height: 64px;
  fill: var(--primary-light);
}

.mattress-info {
  flex: 1;
}

.mattress-info h3 {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.mattress-price {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 8px;
}

.mattress-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 12px;
}

.badge {
  display: inline-block;
  padding: 4px 10px;
  background: var(--primary-bg);
  color: var(--primary);
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-weight: 600;
}

.mattress-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 16px;
}

.mattress-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  background: var(--primary);
  color: #fff;
  border-radius: var(--radius-md);
  font-family: var(--font-primary);
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  transition: all var(--transition-fast);
}

.mattress-btn:hover {
  background: var(--primary-dark);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

/* Disclosure */
.affiliate-disclosure {
  background: var(--primary-bg);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin: 24px 0;
}

/* ============================================
   Footer
   ============================================ */
.site-footer {
  background: var(--surface);
  border-top: 1px solid var(--surface-border);
  padding: 40px 24px;
  margin-top: 48px;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  text-align: center;
}

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px 20px;
  margin-bottom: 20px;
}

.footer-nav a {
  font-size: 0.9rem;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

.footer-nav a:hover {
  color: var(--primary);
}

.footer-copy {
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.footer-affiliate {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 12px;
  font-style: italic;
}

/* ============================================
   Utility Classes
   ============================================ */
.text-center { text-align: center; }
.mt-0 { margin-top: 0; }
.mt-2 { margin-top: 8px; }
.mt-4 { margin-top: 16px; }
.mt-6 { margin-top: 24px; }
.mt-8 { margin-top: 32px; }
.mb-0 { margin-bottom: 0; }
.mb-2 { margin-bottom: 8px; }
.mb-4 { margin-bottom: 16px; }
.mb-6 { margin-bottom: 24px; }
.mb-8 { margin-bottom: 32px; }

.highlight-box {
  background: var(--primary-bg);
  border-left: 4px solid var(--primary);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 16px 20px;
  margin: 16px 0;
}

.highlight-box p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin: 0;
}

.warning-box {
  background: var(--warning-bg);
  border-left: 4px solid var(--warning);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 16px 20px;
  margin: 16px 0;
}

.warning-box p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin: 0;
}

.success-box {
  background: var(--success-bg);
  border-left: 4px solid var(--success);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 16px 20px;
  margin: 16px 0;
}

.success-box p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin: 0;
}

/* Inline icons */
.icon-inline {
  width: 18px;
  height: 18px;
  fill: var(--primary);
  vertical-align: text-bottom;
  margin-right: 4px;
}

/* Hidden utility */
.hidden { display: none !important; }

/* ============================================
   Accessibility
   ============================================ */

/* Skip link */
.skip-link {
  position: absolute;
  top: -100%;
  left: 0;
  background: var(--primary);
  color: #fff;
  padding: 8px 16px;
  z-index: 9999;
  font-weight: 600;
  border-radius: 0 0 8px 0;
  transition: top 0.2s;
}
.skip-link:focus {
  top: 0;
}

/* Visually hidden (screen reader only) */
.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;
}

/* Focus styles */
*:focus {
  outline: none;
}
*:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
  border-radius: 4px;
}
button:focus-visible,
a:focus-visible,
input:focus-visible,
select:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
}

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

/* High contrast mode */
@media (forced-colors: active) {
  .mode-btn.active {
    border: 3px solid ButtonText;
  }
  .age-option.active {
    border: 3px solid ButtonText;
  }
}

/* ============================================
   Accessibility Settings Panel
   ============================================ */
.a11y-toggle {
  background: none;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 8px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: color var(--transition-fast), background var(--transition-fast);
}
.a11y-toggle:hover,
.a11y-toggle:focus-visible {
  color: var(--primary);
  background: var(--primary-bg);
}

.a11y-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 9998;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-normal), visibility var(--transition-normal);
}
.a11y-overlay.active {
  opacity: 1;
  visibility: visible;
}

.a11y-panel {
  position: fixed;
  top: 0;
  right: -360px;
  width: 340px;
  max-width: 90vw;
  height: 100vh;
  background: var(--surface);
  box-shadow: var(--shadow-lg);
  z-index: 9999;
  transition: right var(--transition-normal);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}
.a11y-panel.open {
  right: 0;
}

.a11y-panel-header {
  padding: 20px 24px;
  border-bottom: 1px solid var(--surface-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.a11y-panel-header h2 {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
  margin: 0;
}
.a11y-panel-close {
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--text-muted);
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 8px;
  line-height: 1;
  transition: color var(--transition-fast), background var(--transition-fast);
}
.a11y-panel-close:hover,
.a11y-panel-close:focus-visible {
  color: var(--text);
  background: var(--primary-bg);
}

.a11y-panel-body {
  padding: 16px 24px;
  flex: 1;
}

.a11y-option {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0;
  border-bottom: 1px solid var(--surface-border);
}
.a11y-option:last-child {
  border-bottom: none;
}

.a11y-option-info {
  flex: 1;
  min-width: 0;
}
.a11y-option-label {
  display: block;
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--text);
  margin-bottom: 2px;
  cursor: pointer;
}
.a11y-option-desc {
  display: block;
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.4;
}

/* Toggle Switch */
.a11y-switch {
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
  flex-shrink: 0;
  margin-left: 16px;
}
.a11y-switch-track {
  display: block;
  width: 48px;
  height: 26px;
  background: var(--text-muted);
  border-radius: 13px;
  position: relative;
  transition: background var(--transition-fast);
}
.a11y-switch[aria-checked="true"] .a11y-switch-track {
  background: var(--primary);
}
.a11y-switch-thumb {
  display: block;
  width: 22px;
  height: 22px;
  background: #fff;
  border-radius: 50%;
  position: absolute;
  top: 2px;
  left: 2px;
  transition: transform var(--transition-fast);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}
.a11y-switch[aria-checked="true"] .a11y-switch-thumb {
  transform: translateX(22px);
}

.a11y-panel-footer {
  padding: 16px 24px;
  border-top: 1px solid var(--surface-border);
}
.a11y-note {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-align: center;
}

/* Accessibility mode styles */
[data-a11y-high-contrast="true"] {
  --text-muted: #636e72 !important;
  --surface-border: rgba(0, 0, 0, 0.25) !important;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.15) !important;
  --shadow-md: 0 4px 15px rgba(0, 0, 0, 0.25) !important;
}
[data-theme="dark"][data-a11y-high-contrast="true"] {
  --text-muted: #c8c8e8 !important;
  --text-secondary: #d0d0f0 !important;
  --surface-border: rgba(255, 255, 255, 0.2) !important;
}

[data-a11y-large-text="true"] {
  font-size: 20px !important;
}

[data-a11y-dyslexia-font="true"] body,
[data-a11y-dyslexia-font="true"] input,
[data-a11y-dyslexia-font="true"] button,
[data-a11y-dyslexia-font="true"] select,
[data-a11y-dyslexia-font="true"] textarea {
  font-family: 'OpenDyslexic', 'Open Dyslexic', var(--font-primary) !important;
}

[data-a11y-reduce-motion="true"] *,
[data-a11y-reduce-motion="true"] *::before,
[data-a11y-reduce-motion="true"] *::after {
  animation-duration: 0.01ms !important;
  animation-iteration-count: 1 !important;
  transition-duration: 0.01ms !important;
  scroll-behavior: auto !important;
}

/* Ensure the header has space for both toggles */
.header-inner {
  gap: 8px;
}
.header-actions {
  display: flex;
  align-items: center;
  gap: 4px;
}

/* Print styles */
@media print {
  .site-header, .site-footer, .theme-toggle, .share-btn, .a11y-toggle, .a11y-panel, .a11y-overlay { display: none !important; }
  body { background: #fff; color: #000; }
  .calc-container, .card { box-shadow: none; border: 1px solid #ddd; }
}