/* Telegram 下载网站样式 */

/* ===== CSS Reset & Variables ===== */
:root {
  --primary: #0088cc;
  --primary-dark: #006699;
  --secondary: #229ED9;
  --accent: #7C3AED;
  --bg-light: #F8FAFC;
  --bg-card: #FFFFFF;
  --text-primary: #1E293B;
  --text-secondary: #64748B;
  --success: #10B981;
  --border: #E2E8F0;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background: var(--bg-light);
  color: var(--text-primary);
  line-height: 1.6;
}

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

ul {
  list-style: none;
}

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

/* ===== Layout ===== */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.section {
  padding: 80px 0;
}

/* ===== Header ===== */
.header {
  background: var(--bg-card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 70px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary);
}

.logo svg {
  width: 32px;
  height: 32px;
}

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

.nav a {
  padding: 8px 16px;
  border-radius: 8px;
  font-weight: 500;
  transition: all 0.2s;
  color: var(--text-secondary);
}

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

.mobile-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

/* ===== Hero Section ===== */
.hero {
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  color: white;
  padding: 100px 0;
  text-align: center;
}

.hero h1 {
  font-size: 3rem;
  font-weight: 800;
  margin-bottom: 20px;
}

.hero p {
  font-size: 1.25rem;
  opacity: 0.9;
  max-width: 600px;
  margin: 0 auto 30px;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 28px;
  border-radius: 12px;
  font-weight: 600;
  font-size: 1rem;
  transition: all 0.3s;
  cursor: pointer;
  border: none;
}

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

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(0,0,0,0.2);
}

.btn-secondary {
  background: rgba(255,255,255,0.2);
  color: white;
  border: 2px solid white;
}

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

.btn-download {
  background: var(--primary);
  color: white;
  padding: 12px 24px;
  border-radius: 10px;
  font-weight: 600;
  transition: all 0.2s;
}

.btn-download:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
}

/* ===== Cards ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
  margin-top: 40px;
}

.card {
  background: var(--bg-card);
  border-radius: 16px;
  padding: 28px;
  box-shadow: var(--shadow);
  transition: all 0.3s;
  border: 1px solid var(--border);
}

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

.card-icon {
  width: 56px;
  height: 56px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  color: white;
}

.card h3 {
  font-size: 1.25rem;
  margin-bottom: 12px;
  color: var(--text-primary);
}

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

/* ===== Platform Cards ===== */
.platform-card {
  text-align: center;
  padding: 32px;
}

.platform-card .platform-icon {
  font-size: 4rem;
  margin-bottom: 16px;
}

.platform-card h3 {
  font-size: 1.5rem;
}

.platform-card .version {
  color: var(--success);
  font-size: 0.875rem;
  margin: 8px 0 16px;
}

/* ===== Features List ===== */
.features-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 32px;
  margin-top: 40px;
}

.feature-item {
  display: flex;
  gap: 20px;
  padding: 24px;
  background: var(--bg-card);
  border-radius: 12px;
  border: 1px solid var(--border);
}

.feature-item .icon {
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  flex-shrink: 0;
}

.feature-item h4 {
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.feature-item p {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* ===== FAQ Accordion ===== */
.faq-item {
  background: var(--bg-card);
  border-radius: 12px;
  margin-bottom: 16px;
  border: 1px solid var(--border);
  overflow: hidden;
}

.faq-question {
  width: 100%;
  padding: 20px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: none;
  border: none;
  cursor: pointer;
  font-size: 1.05rem;
  font-weight: 600;
  text-align: left;
  color: var(--text-primary);
  transition: background 0.2s;
}

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

.faq-question svg {
  transition: transform 0.3s;
  flex-shrink: 0;
}

.faq-item.active .faq-question svg {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease-out;
}

.faq-answer-inner {
  padding: 0 24px 20px;
  color: var(--text-secondary);
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  max-height: 500px;
}

/* ===== Breadcrumb ===== */
.breadcrumb {
  padding: 16px 0;
  font-size: 0.875rem;
  color: var(--text-secondary);
}

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

.breadcrumb span {
  margin: 0 8px;
}

/* ===== Page Header ===== */
.page-header {
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  color: white;
  padding: 60px 0;
  text-align: center;
}

.page-header h1 {
  font-size: 2.5rem;
  margin-bottom: 12px;
}

.page-header p {
  opacity: 0.9;
  max-width: 600px;
  margin: 0 auto;
}

/* ===== Footer ===== */
.footer {
  background: var(--text-primary);
  color: white;
  padding: 60px 0 30px;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 40px;
  margin-bottom: 40px;
}

.footer h4 {
  font-size: 1.1rem;
  margin-bottom: 20px;
  color: var(--primary);
}

.footer a {
  display: block;
  padding: 6px 0;
  color: rgba(255,255,255,0.7);
  transition: color 0.2s;
}

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

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 30px;
  text-align: center;
  color: rgba(255,255,255,0.5);
  font-size: 0.875rem;
}

/* ===== Related Links ===== */
.related-links {
  background: var(--bg-card);
  border-radius: 16px;
  padding: 32px;
  margin-top: 60px;
  border: 1px solid var(--border);
}

.related-links h3 {
  margin-bottom: 20px;
  font-size: 1.25rem;
}

.related-links ul {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 12px;
}

.related-links a {
  color: var(--primary);
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  background: var(--bg-light);
  border-radius: 8px;
  transition: all 0.2s;
}

.related-links a:hover {
  background: var(--primary);
  color: white;
}

/* ===== Back to Top ===== */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s;
  box-shadow: var(--shadow-lg);
}

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

.back-to-top:hover {
  transform: translateY(-4px);
  background: var(--primary-dark);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .nav {
    display: none;
    position: absolute;
    top: 70px;
    left: 0;
    right: 0;
    background: var(--bg-card);
    flex-direction: column;
    padding: 20px;
    border-bottom: 1px solid var(--border);
  }

  .nav.active {
    display: flex;
  }

  .mobile-toggle {
    display: block;
  }

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

  .hero p {
    font-size: 1rem;
  }

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

  .section {
    padding: 60px 0;
  }

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

/* ===== Animations ===== */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeInUp 0.6s ease-out;
}

/* ===== Stats ===== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 40px;
}

.stat-item {
  text-align: center;
  padding: 32px;
  background: var(--bg-card);
  border-radius: 16px;
  border: 1px solid var(--border);
}

.stat-number {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 8px;
}

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