/* ============================================
   Chinese Xiehouyu English Guide - Stylesheet
   yiqidao.com/xiehouyu/
   ============================================ */

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

:root {
  --color-bg: #faf8f5;
  --color-surface: #ffffff;
  --color-text: #2c2c2c;
  --color-text-secondary: #666;
  --color-accent: #c0392b;
  --color-accent-light: #e74c3c;
  --color-gold: #d4a843;
  --color-gold-light: #f0d78c;
  --color-ink: #1a1a2e;
  --color-border: #e8e0d4;
  --color-tag-bg: #fdf2e9;
  --color-tag-text: #c0392b;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.12);
  --shadow-hover: 0 12px 40px rgba(0,0,0,0.15);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --font-display: 'Noto Serif SC', 'Songti SC', 'SimSun', Georgia, serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --max-width: 1200px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
}

/* === Typography === */
h1, h2, h3, h4 { font-family: var(--font-display); font-weight: 700; line-height: 1.3; }

/* === Header / Nav === */
.site-header {
  background: linear-gradient(135deg, var(--color-ink) 0%, #16213e 100%);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-md);
}

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

.site-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: #fff;
}

.site-logo .logo-icon {
  font-size: 28px;
}

.site-logo .logo-text {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 1px;
}

.site-logo .logo-sub {
  font-size: 12px;
  opacity: 0.7;
  font-weight: 400;
  display: block;
  letter-spacing: 0.5px;
}

.main-nav { display: flex; gap: 8px; }

.main-nav a {
  color: rgba(255,255,255,0.8);
  text-decoration: none;
  font-size: 14px;
  padding: 6px 14px;
  border-radius: 20px;
  transition: var(--transition);
}

.main-nav a:hover, .main-nav a.active {
  color: #fff;
  background: rgba(255,255,255,0.15);
}

/* Mobile Nav Toggle */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: #fff;
  font-size: 24px;
  cursor: pointer;
  padding: 8px;
}

/* === Hero Section === */
.hero {
  background: linear-gradient(135deg, var(--color-ink) 0%, #16213e 50%, #0f3460 100%);
  color: #fff;
  padding: 80px 24px 60px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23d4a843' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
  opacity: 0.4;
}

.hero-content { position: relative; max-width: 800px; margin: 0 auto; }

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.2rem);
  margin-bottom: 16px;
  background: linear-gradient(135deg, #fff 0%, var(--color-gold-light) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero .hero-chinese {
  font-size: clamp(1.2rem, 3vw, 1.8rem);
  color: var(--color-gold);
  margin-bottom: 20px;
  font-family: var(--font-display);
}

.hero p {
  font-size: clamp(0.95rem, 2vw, 1.1rem);
  opacity: 0.85;
  max-width: 600px;
  margin: 0 auto;
  line-height: 1.8;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 40px;
  margin-top: 32px;
  flex-wrap: wrap;
}

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

.hero-stat .stat-num {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-gold);
  display: block;
}

.hero-stat .stat-label {
  font-size: 0.85rem;
  opacity: 0.7;
}

/* === Category Hero === */
.category-hero {
  padding: 50px 24px 40px;
}

.category-hero .cat-icon {
  font-size: 48px;
  margin-bottom: 12px;
  display: block;
}

.category-hero h1 {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  margin-bottom: 8px;
}

.category-hero .cat-subtitle {
  font-size: 1rem;
  opacity: 0.7;
  max-width: 600px;
}

/* === Breadcrumb === */
.breadcrumb {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: rgba(255,255,255,0.6);
}

.breadcrumb a {
  color: rgba(255,255,255,0.7);
  text-decoration: none;
  transition: var(--transition);
}

.breadcrumb a:hover { color: var(--color-gold); }

.breadcrumb .sep { opacity: 0.4; }

/* === Section === */
.section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 40px 24px;
}

.section-title {
  font-size: 1.6rem;
  margin-bottom: 8px;
  color: var(--color-ink);
}

.section-desc {
  color: var(--color-text-secondary);
  margin-bottom: 32px;
  font-size: 0.95rem;
}

/* === Category Grid (Index Page) === */
.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 24px;
}

.category-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
  transition: var(--transition);
  text-decoration: none;
  color: inherit;
  display: block;
  position: relative;
  overflow: hidden;
}

.category-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-gold));
  transform: scaleX(0);
  transform-origin: left;
  transition: var(--transition);
}

.category-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.category-card:hover::before { transform: scaleX(1); }

.category-card .card-icon {
  font-size: 40px;
  margin-bottom: 16px;
  display: block;
}

.category-card .card-num {
  font-size: 0.8rem;
  color: var(--color-accent);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-bottom: 8px;
}

.category-card h2 {
  font-size: 1.25rem;
  margin-bottom: 6px;
  color: var(--color-ink);
}

.category-card .card-subtitle {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  margin-bottom: 16px;
}

.category-card .card-count {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.82rem;
  color: var(--color-accent);
  background: var(--color-tag-bg);
  padding: 4px 12px;
  border-radius: 20px;
}

/* === Proverb List (Category Page) === */
.proverb-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.proverb-item {
  background: var(--color-surface);
  border-radius: var(--radius-md);
  padding: 24px 28px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
  transition: var(--transition);
  text-decoration: none;
  color: inherit;
  display: block;
}

.proverb-item:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-gold);
}

.proverb-item .item-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--color-tag-bg);
  color: var(--color-accent);
  font-size: 0.82rem;
  font-weight: 700;
  margin-right: 12px;
  flex-shrink: 0;
}

.proverb-item .item-header {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  margin-bottom: 10px;
}

.proverb-item h3 {
  font-size: 1.1rem;
  color: var(--color-ink);
  flex: 1;
}

.proverb-item .item-idiom {
  font-size: 0.9rem;
  color: var(--color-accent);
  font-style: italic;
  margin-bottom: 8px;
  padding-left: 44px;
}

.proverb-item .item-intro {
  font-size: 0.88rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
  padding-left: 44px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* === Proverb Detail Page === */
.proverb-detail {
  max-width: 800px;
  margin: 0 auto;
  padding: 40px 24px 80px;
}

.proverb-header {
  margin-bottom: 40px;
  padding-bottom: 32px;
  border-bottom: 2px solid var(--color-border);
}

.proverb-header .detail-num {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--color-accent);
  background: var(--color-tag-bg);
  padding: 4px 16px;
  border-radius: 20px;
  margin-bottom: 16px;
}

.proverb-header h1 {
  font-size: clamp(1.5rem, 4vw, 2.2rem);
  color: var(--color-ink);
  margin-bottom: 12px;
}

.proverb-header .detail-idiom {
  font-size: 1.15rem;
  color: var(--color-accent);
  font-style: italic;
  margin-bottom: 8px;
}

.proverb-header .detail-chinese {
  font-size: 1rem;
  color: var(--color-text-secondary);
  font-family: var(--font-display);
}

.detail-section {
  margin-bottom: 32px;
}

.detail-section h2 {
  font-size: 1.15rem;
  color: var(--color-ink);
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  gap: 8px;
}

.detail-section h2 .sec-icon {
  font-size: 1.2rem;
}

.detail-section p {
  font-size: 0.95rem;
  line-height: 1.8;
  color: var(--color-text);
}

.detail-section .example-item {
  background: var(--color-tag-bg);
  border-left: 3px solid var(--color-gold);
  padding: 14px 18px;
  margin-bottom: 10px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-size: 0.92rem;
  line-height: 1.7;
}

.detail-section .example-item strong {
  color: var(--color-accent);
}

/* Tags */
.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.tag {
  font-size: 0.78rem;
  padding: 4px 12px;
  border-radius: 20px;
  background: var(--color-tag-bg);
  color: var(--color-tag-text);
  font-weight: 500;
}

/* === Category Nav (Prev/Next) === */
.proverb-nav {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-top: 48px;
  padding-top: 32px;
  border-top: 2px solid var(--color-border);
}

.proverb-nav a {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  color: var(--color-accent);
  font-size: 0.9rem;
  font-weight: 500;
  padding: 10px 20px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  transition: var(--transition);
}

.proverb-nav a:hover {
  background: var(--color-tag-bg);
  border-color: var(--color-gold);
}

.proverb-nav .nav-label {
  font-size: 0.75rem;
  color: var(--color-text-secondary);
  display: block;
}

/* === Footer === */
footer {
  background: var(--color-ink);
  color: rgba(255,255,255,0.7);
  padding: 0;
  font-size: 0.85rem;
  position: relative;
  overflow: hidden;
}

footer::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-gold), var(--color-accent));
}

.seal-stamp {
  display: block;
  margin: 0 auto;
  padding-top: 40px;
  opacity: 0.6;
  filter: grayscale(20%);
  transition: var(--transition);
}

.seal-stamp:hover {
  opacity: 0.9;
  transform: rotate(-5deg) scale(1.05);
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 32px 24px 24px;
  display: flex;
  gap: 48px;
  align-items: flex-start;
}

.footer-brand {
  flex: 0 0 280px;
}

.footer-logo {
  font-family: var(--font-display);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--color-gold);
  margin-bottom: 12px;
  letter-spacing: 2px;
}

.footer-desc {
  font-size: 0.85rem;
  line-height: 1.7;
  color: rgba(255,255,255,0.5);
}

.footer-links {
  flex: 1;
  display: flex;
  gap: 36px;
  justify-content: flex-end;
}

.footer-col h4 {
  font-family: var(--font-display);
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--color-gold);
  margin-bottom: 14px;
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

.footer-col ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-col li {
  margin-bottom: 8px;
}

.footer-col a {
  color: rgba(255,255,255,0.6);
  text-decoration: none;
  font-size: 0.82rem;
  transition: var(--transition);
  display: inline-block;
}

.footer-col a:hover {
  color: var(--color-gold);
  transform: translateX(3px);
}

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.08);
  padding: 16px 24px;
  text-align: center;
}

.footer-bottom p {
  font-size: 0.78rem;
  color: rgba(255,255,255,0.4);
  margin: 0;
}

.footer-bottom a {
  color: rgba(255,255,255,0.5);
  text-decoration: none;
  transition: var(--transition);
}

.footer-bottom a:hover {
  color: var(--color-gold);
}

/* === Back to Top === */
.back-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-accent);
  color: #fff;
  border: none;
  font-size: 20px;
  cursor: pointer;
  box-shadow: var(--shadow-md);
  opacity: 0;
  transform: translateY(10px);
  transition: var(--transition);
  z-index: 50;
}

.back-top.visible {
  opacity: 1;
  transform: translateY(0);
}

.back-top:hover {
  background: var(--color-accent-light);
  transform: translateY(-2px);
}

/* === Responsive === */
@media (max-width: 768px) {
  .header-inner { height: 56px; }
  .main-nav {
    display: none;
    position: absolute;
    top: 56px;
    left: 0; right: 0;
    background: var(--color-ink);
    flex-direction: column;
    padding: 16px 24px;
    box-shadow: var(--shadow-md);
  }
  .main-nav.open { display: flex; }
  .nav-toggle { display: block; }
  .hero { padding: 50px 20px 40px; }
  .hero-stats { gap: 24px; }
  .category-grid { grid-template-columns: 1fr; }
  .proverb-item { padding: 18px 20px; }
  .proverb-item .item-idiom,
  .proverb-item .item-intro { padding-left: 0; }
  .proverb-nav { flex-direction: column; }
  .proverb-detail { padding: 24px 16px 60px; }
  .footer-inner {
    flex-direction: column;
    gap: 24px;
    padding: 24px 16px 16px;
  }
  .footer-brand { flex: none; }
  .footer-links {
    flex-direction: column;
    gap: 24px;
    align-items: flex-start;
  }
}

@media (max-width: 480px) {
  .hero h1 { font-size: 1.6rem; }
  .category-card { padding: 24px; }
  .proverb-header h1 { font-size: 1.4rem; }
}