/* ===== CSS Variables (Root Design Tokens) ===== */
:root {
  --color-primary: #6c5ce7;
  --color-primary-dark: #5a4bd1;
  --color-secondary: #00cec9;
  --color-accent: #fd79a8;
  --color-bg: #0f0f1a;
  --color-bg-secondary: #1a1a2e;
  --color-bg-card: #16213e;
  --color-text: #e0e0e0;
  --color-text-muted: #a0a0b0;
  --color-text-heading: #ffffff;
  --color-border: #2d2d44;
  --color-success: #00b894;
  --color-warning: #fdcb6e;
  --color-danger: #e17055;
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.2);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.3);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.4);
  --transition: 0.3s ease;
  --max-width: 1200px;
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

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

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

ul, ol {
  list-style: none;
}

/* ===== Layout ===== */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-sm);
}

main {
  flex: 1;
}

/* ===== Header & Navigation ===== */
.site-header {
  background: var(--color-bg-secondary);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 1000;
  padding: var(--spacing-sm) 0;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text-heading);
}

.site-logo img {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
}

.nav-menu {
  display: flex;
  gap: var(--spacing-md);
  align-items: center;
}

.nav-menu a {
  color: var(--color-text);
  font-size: 0.9rem;
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-sm);
  transition: background var(--transition), color var(--transition);
}

.nav-menu a:hover, .nav-menu a.active {
  background: var(--color-primary);
  color: #fff;
}

/* Mobile Menu Toggle */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--color-text);
  font-size: 1.5rem;
  cursor: pointer;
  padding: var(--spacing-xs);
}

/* ===== Hero / Search Section ===== */
.hero-search {
  text-align: center;
  padding: var(--spacing-xl) 0;
  background: linear-gradient(135deg, var(--color-bg-secondary) 0%, var(--color-bg) 100%);
}

.hero-search h1 {
  font-size: 2.5rem;
  color: var(--color-text-heading);
  margin-bottom: var(--spacing-sm);
}

.hero-search .subtitle {
  font-size: 1.1rem;
  color: var(--color-text-muted);
  margin-bottom: var(--spacing-lg);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.search-box {
  max-width: 640px;
  margin: 0 auto var(--spacing-md);
  position: relative;
}

.search-box input {
  width: 100%;
  padding: 1rem 3.5rem 1rem 1.25rem;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-bg-card);
  color: var(--color-text);
  font-size: 1rem;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.search-box input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 4px rgba(108,92,231,0.2);
}

.search-box button {
  position: absolute;
  right: 8px;
  top: 50%;
  transform: translateY(-50%);
  background: var(--color-primary);
  border: none;
  color: #fff;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1.1rem;
  transition: background var(--transition);
}

.search-box button:hover {
  background: var(--color-primary-dark);
}

/* Search Suggestions */
.search-suggestions {
  display: none;
  position: absolute;
  top: calc(100% + 4px);
  left: 0;
  right: 0;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  z-index: 100;
  max-height: 300px;
  overflow-y: auto;
}

.search-suggestions.active {
  display: block;
}

.search-suggestions a {
  display: block;
  padding: var(--spacing-xs) var(--spacing-sm);
  color: var(--color-text);
  border-bottom: 1px solid var(--color-border);
}

.search-suggestions a:last-child {
  border-bottom: none;
}

.search-suggestions a:hover {
  background: var(--color-bg-secondary);
}

/* Hot Tags */
.hot-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--spacing-xs);
  margin-top: var(--spacing-sm);
}

.hot-tags a {
  display: inline-block;
  padding: 4px 12px;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  color: var(--color-text-muted);
  transition: all var(--transition);
}

.hot-tags a:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: rgba(108,92,231,0.1);
}

/* ===== Section Styles ===== */
.section {
  padding: var(--spacing-xl) 0;
}

.section-title {
  font-size: 1.5rem;
  color: var(--color-text-heading);
  margin-bottom: var(--spacing-md);
  padding-bottom: var(--spacing-xs);
  border-bottom: 2px solid var(--color-primary);
  display: inline-block;
}

/* ===== Card Grid ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--spacing-md);
}

.card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  transition: transform var(--transition), box-shadow var(--transition);
}

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

.card h3 {
  color: var(--color-text-heading);
  margin-bottom: var(--spacing-xs);
  font-size: 1.1rem;
}

.card p {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin-bottom: var(--spacing-sm);
}

.card .card-meta {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.card .card-tag {
  display: inline-block;
  padding: 2px 8px;
  background: rgba(108,92,231,0.15);
  color: var(--color-primary);
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  margin-right: 4px;
}

/* ===== Tag Cloud ===== */
.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
}

.tag-cloud a {
  padding: 6px 14px;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  font-size: 0.85rem;
  color: var(--color-text);
  transition: all var(--transition);
}

.tag-cloud a:hover {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

/* ===== FAQ Accordion ===== */
.faq-list {
  max-width: 800px;
}

.faq-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-sm);
  overflow: hidden;
}

.faq-question {
  width: 100%;
  background: var(--color-bg-card);
  border: none;
  color: var(--color-text-heading);
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: 1rem;
  text-align: left;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background var(--transition);
}

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

.faq-question::after {
  content: "+";
  font-size: 1.2rem;
  transition: transform var(--transition);
}

.faq-item.active .faq-question::after {
  transform: rotate(45deg);
}

.faq-answer {
  display: none;
  padding: var(--spacing-sm) var(--spacing-md);
  color: var(--color-text-muted);
  line-height: 1.8;
  background: var(--color-bg);
}

.faq-item.active .faq-answer {
  display: block;
}

/* ===== Breadcrumb ===== */
.breadcrumb {
  padding: var(--spacing-sm) 0;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

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

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

.breadcrumb span {
  margin: 0 6px;
}

/* ===== Footer ===== */
.site-footer {
  background: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-xl) 0 var(--spacing-md);
  margin-top: var(--spacing-xl);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
}

.footer-col h4 {
  color: var(--color-text-heading);
  margin-bottom: var(--spacing-sm);
  font-size: 1rem;
}

.footer-col a {
  display: block;
  color: var(--color-text-muted);
  font-size: 0.9rem;
  padding: 4px 0;
}

.footer-col a:hover {
  color: var(--color-secondary);
}

.footer-bottom {
  text-align: center;
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--color-border);
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* ===== Back to Top ===== */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 44px;
  height: 44px;
  background: var(--color-primary);
  color: #fff;
  border: none;
  border-radius: 50%;
  font-size: 1.2rem;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition);
  z-index: 999;
  box-shadow: var(--shadow-sm);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background: var(--color-primary-dark);
  transform: translateY(-2px);
}

/* ===== PWA Install Banner ===== */
.pwa-banner {
  display: none;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: var(--color-bg-card);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-sm) var(--spacing-md);
  z-index: 1001;
  box-shadow: var(--shadow-lg);
}

.pwa-banner.show {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.pwa-banner p {
  font-size: 0.9rem;
  color: var(--color-text);
}

.pwa-banner .btn-install {
  background: var(--color-primary);
  color: #fff;
  border: none;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.85rem;
}

.pwa-banner .btn-dismiss {
  background: none;
  border: none;
  color: var(--color-text-muted);
  cursor: pointer;
  font-size: 1.2rem;
  margin-left: var(--spacing-sm);
}

/* ===== Buttons ===== */
.btn {
  display: inline-block;
  padding: 10px 24px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  border: none;
  text-align: center;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-primary-dark);
  color: #fff;
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--color-primary);
  color: var(--color-primary);
}

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

/* ===== Notice / Alert ===== */
.notice {
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-md);
  font-size: 0.9rem;
}

.notice-info {
  background: rgba(108,92,231,0.1);
  border: 1px solid var(--color-primary);
  color: var(--color-text);
}

.notice-warning {
  background: rgba(253,203,110,0.1);
  border: 1px solid var(--color-warning);
  color: var(--color-warning);
}

/* ===== Search Results ===== */
.search-results {
  margin-top: var(--spacing-md);
}

.search-result-item {
  padding: var(--spacing-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-sm);
  background: var(--color-bg-card);
  transition: border-color var(--transition);
}

.search-result-item:hover {
  border-color: var(--color-primary);
}

.search-result-item h3 {
  color: var(--color-secondary);
  margin-bottom: 4px;
  font-size: 1.05rem;
}

.search-result-item .result-url {
  font-size: 0.8rem;
  color: var(--color-success);
  margin-bottom: 6px;
}

.search-result-item p {
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

.no-results {
  text-align: center;
  padding: var(--spacing-xl);
  color: var(--color-text-muted);
}

/* ===== Timeline ===== */
.timeline {
  position: relative;
  padding-left: 30px;
}

.timeline::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--color-border);
}

.timeline-item {
  position: relative;
  margin-bottom: var(--spacing-md);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--color-bg-card);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}

.timeline-item::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 18px;
  width: 12px;
  height: 12px;
  background: var(--color-primary);
  border-radius: 50%;
}

.timeline-item .date {
  font-size: 0.8rem;
  color: var(--color-primary);
  margin-bottom: 4px;
}

/* ===== Form ===== */
.form-group {
  margin-bottom: var(--spacing-md);
}

.form-group label {
  display: block;
  margin-bottom: 6px;
  font-size: 0.9rem;
  color: var(--color-text);
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 10px 14px;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text);
  font-size: 0.9rem;
  transition: border-color var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-primary);
}

.form-group textarea {
  min-height: 120px;
  resize: vertical;
}

/* ===== Toast ===== */
.toast {
  position: fixed;
  top: 80px;
  right: 20px;
  background: var(--color-success);
  color: #fff;
  padding: 12px 20px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  z-index: 2000;
  opacity: 0;
  transform: translateX(100%);
  transition: all var(--transition);
}

.toast.show {
  opacity: 1;
  transform: translateX(0);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }

  .nav-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-bg-secondary);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    padding: var(--spacing-sm);
    gap: 4px;
  }

  .nav-menu.active {
    display: flex;
  }

  .nav-menu a {
    padding: var(--spacing-sm);
    border-radius: var(--radius-sm);
  }

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

  .hero-search .subtitle {
    font-size: 0.95rem;
  }

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

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

  .section-title {
    font-size: 1.25rem;
  }
}

@media (max-width: 480px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .hero-search {
    padding: var(--spacing-lg) 0;
  }
}

/* ===== Utility Classes ===== */
.text-center { text-align: center; }
.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }