/* =============================================
   91网 官方网站 - 极简高端风格 CSS
   ============================================= */
:root {
  --primary: #1a1a2e;
  --accent: #0077ff;
  --accent2: #00c6ff;
  --bg: #ffffff;
  --bg2: #f7f8fc;
  --text: #1a1a2e;
  --text-light: #6b7280;
  --border: #e5e7eb;
  --radius: 10px;
  --shadow: 0 4px 24px rgba(0,0,0,0.07);
  --transition: 0.3s ease;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { text-decoration: none; color: inherit; transition: color var(--transition); }
a:hover { color: var(--accent); }
img { max-width: 100%; height: auto; display: block; }
ul { list-style: none; }

.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

/* ---- HEADER ---- */
.header {
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 200;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  gap: 20px;
}

.logo img { height: 38px; width: auto; }

.nav ul {
  display: flex;
  gap: 28px;
}

.nav a {
  font-size: 15px;
  font-weight: 500;
  color: var(--text);
  padding: 4px 0;
  border-bottom: 2px solid transparent;
  transition: all var(--transition);
}

.nav a:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 22px;
  cursor: pointer;
  color: var(--text);
}

/* Search Bar */
.search-bar {
  background: var(--bg2);
  border-top: 1px solid var(--border);
  padding: 10px 0;
}

.search-inner {
  display: flex;
  max-width: 600px;
  margin: 0 auto;
  gap: 0;
}

.search-inner input {
  flex: 1;
  padding: 10px 16px;
  border: 1px solid var(--border);
  border-right: none;
  border-radius: var(--radius) 0 0 var(--radius);
  font-size: 14px;
  outline: none;
  background: var(--bg);
  color: var(--text);
  transition: border-color var(--transition);
}

.search-inner input:focus { border-color: var(--accent); }

.search-inner button {
  padding: 10px 20px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 0 var(--radius) var(--radius) 0;
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  transition: background var(--transition);
  white-space: nowrap;
}

.search-inner button:hover { background: var(--primary); }

/* ---- HERO ---- */
.hero {
  position: relative;
  min-height: 520px;
  display: flex;
  align-items: center;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  overflow: hidden;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(10,10,40,0.82) 0%, rgba(0,80,180,0.55) 100%);
}

.hero-content {
  position: relative;
  z-index: 2;
  color: #fff;
  text-align: center;
  padding: 80px 24px;
}

.hero-content h1 {
  font-size: clamp(28px, 5vw, 56px);
  font-weight: 800;
  letter-spacing: -1px;
  margin-bottom: 20px;
  line-height: 1.2;
}

.hero-content p {
  font-size: clamp(15px, 2vw, 20px);
  opacity: 0.9;
  margin-bottom: 36px;
  line-height: 1.8;
}

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

/* ---- BUTTONS ---- */
.btn {
  display: inline-block;
  padding: 12px 28px;
  border-radius: 6px;
  font-weight: 600;
  font-size: 15px;
  cursor: pointer;
  transition: all var(--transition);
  border: 2px solid transparent;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}
.btn-primary:hover { background: #005fcc; border-color: #005fcc; color: #fff; }

.btn-outline {
  background: transparent;
  color: #fff;
  border-color: rgba(255,255,255,0.7);
}
.btn-outline:hover { background: rgba(255,255,255,0.15); color: #fff; }

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

/* ---- INTRO ---- */
.intro-section { padding: 80px 0; background: var(--bg); }

.intro-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.intro-text h2 { font-size: 32px; font-weight: 700; margin-bottom: 20px; }
.intro-text p { color: var(--text-light); margin-bottom: 16px; font-size: 16px; }
.intro-text .btn { margin-top: 8px; }

.intro-img img {
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  width: 100%;
  object-fit: cover;
  max-height: 320px;
}

/* ---- SECTIONS COMMON ---- */
section { padding: 80px 0; }

section h2 {
  font-size: clamp(22px, 3vw, 34px);
  font-weight: 700;
  text-align: center;
  margin-bottom: 12px;
}

.section-desc {
  text-align: center;
  color: var(--text-light);
  font-size: 16px;
  margin-bottom: 48px;
}

.section-more { text-align: center; margin-top: 40px; }

/* ---- VIDEO GRID ---- */
.videos-section { background: var(--bg2); }

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(270px, 1fr));
  gap: 28px;
}

.video-card {
  background: var(--bg);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: transform var(--transition), box-shadow var(--transition);
}

.video-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 32px rgba(0,0,0,0.12);
}

.video-thumb {
  position: relative;
  width: 100%;
  padding-top: 56.25%;
  overflow: hidden;
  cursor: pointer;
  background: #111;
}

.video-thumb img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition), opacity var(--transition);
}

.video-thumb:hover img {
  transform: scale(1.04);
  opacity: 0.75;
}

.play-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity var(--transition);
}

.video-thumb:hover .play-overlay { opacity: 1; }

.play-icon {
  width: 64px;
  height: 64px;
  background: rgba(0,119,255,0.85);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  color: #fff;
  padding-left: 4px;
  box-shadow: 0 4px 20px rgba(0,119,255,0.4);
}

.video-badge {
  position: absolute;
  top: 12px;
  left: 12px;
  background: var(--accent);
  color: #fff;
  font-size: 11px;
  font-weight: 600;
  padding: 3px 8px;
  border-radius: 4px;
  letter-spacing: 0.5px;
}

.video-info { padding: 18px 20px 20px; }
.video-info h3 { font-size: 16px; font-weight: 600; margin-bottom: 8px; line-height: 1.4; }
.video-info h3 a { color: var(--text); }
.video-info h3 a:hover { color: var(--accent); }
.video-desc { font-size: 13px; color: var(--text-light); margin-bottom: 12px; }

.video-meta {
  display: flex;
  gap: 12px;
  font-size: 13px;
  color: var(--text-light);
  margin-bottom: 10px;
}

.video-tags { display: flex; flex-wrap: wrap; gap: 6px; }
.video-tags span {
  font-size: 11px;
  padding: 3px 8px;
  background: var(--bg2);
  color: var(--text-light);
  border-radius: 4px;
  border: 1px solid var(--border);
}

/* ---- STATS ---- */
.stats-section {
  background: linear-gradient(135deg, var(--primary) 0%, #0a3d8f 100%);
  padding: 60px 0;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 40px;
  text-align: center;
}

.stat-item { color: #fff; }

.stat-num {
  display: block;
  font-size: clamp(32px, 5vw, 52px);
  font-weight: 800;
  line-height: 1;
  margin-bottom: 8px;
}

.stat-num em { font-style: normal; font-size: 0.55em; color: var(--accent2); }

.stat-label {
  font-size: 15px;
  opacity: 0.8;
  letter-spacing: 0.5px;
}

/* ---- FEATURES ---- */
.features-section { background: var(--bg); }

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 36px;
}

.feature-item {
  text-align: center;
  padding: 36px 24px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: box-shadow var(--transition), transform var(--transition);
}

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

.feature-icon { font-size: 44px; margin-bottom: 16px; }
.feature-item h3 { font-size: 18px; font-weight: 600; margin-bottom: 10px; }
.feature-item p { color: var(--text-light); font-size: 14px; }

/* ---- REVIEWS ---- */
.reviews-section { background: var(--bg2); }

.review-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}

.review-card {
  background: var(--bg);
  padding: 28px;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  transition: transform var(--transition);
}

.review-card:hover { transform: translateY(-4px); }

.review-stars { color: #f59e0b; font-size: 16px; margin-bottom: 14px; }
.review-text { font-style: italic; color: var(--text-light); margin-bottom: 16px; font-size: 14px; line-height: 1.7; }
.review-author { font-weight: 600; font-size: 13px; text-align: right; color: var(--text); }

/* ---- FAQ ---- */
.faq-section { background: var(--bg); }

.faq-list { max-width: 800px; margin: 0 auto; }

.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 12px;
  overflow: hidden;
  transition: box-shadow var(--transition);
}

.faq-item:hover { box-shadow: var(--shadow); }

.faq-q {
  padding: 18px 22px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  list-style: none;
  background: var(--bg);
  transition: background var(--transition);
}

.faq-q::-webkit-details-marker { display: none; }
.faq-q::after { content: "+"; font-size: 20px; color: var(--accent); transition: transform var(--transition); }
.faq-item[open] .faq-q::after { transform: rotate(45deg); }
.faq-item[open] .faq-q { background: var(--bg2); }

.faq-a {
  padding: 16px 22px 20px;
  color: var(--text-light);
  font-size: 15px;
  border-top: 1px solid var(--border);
  background: var(--bg2);
}

/* ---- CONTACT ---- */
.contact-section { background: var(--bg2); }

.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: 60px;
  align-items: start;
}

.contact-info h3 { font-size: 22px; margin-bottom: 20px; }
.contact-info p { color: var(--text-light); margin-bottom: 10px; font-size: 15px; }

.social-links { margin-top: 24px; }
.social-links h4 { font-size: 16px; margin-bottom: 12px; }
.social-links a {
  display: inline-block;
  margin-right: 10px;
  margin-bottom: 8px;
  padding: 6px 14px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 13px;
  color: var(--text);
  transition: all var(--transition);
}
.social-links a:hover { background: var(--accent); color: #fff; border-color: var(--accent); }

.contact-form h3 { font-size: 22px; margin-bottom: 20px; }
.contact-form input,
.contact-form textarea {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 14px;
  margin-bottom: 14px;
  background: var(--bg);
  color: var(--text);
  outline: none;
  transition: border-color var(--transition);
  font-family: inherit;
}
.contact-form input:focus,
.contact-form textarea:focus { border-color: var(--accent); }
.contact-form textarea { resize: vertical; }
.contact-form .btn { width: 100%; text-align: center; }

/* ---- FOOTER ---- */
.footer { background: var(--primary); color: #fff; padding: 64px 0 0; }

.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: 40px;
  padding-bottom: 48px;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}

.footer-brand img { height: 36px; margin-bottom: 14px; filter: brightness(0) invert(1); }
.footer-brand p { color: rgba(255,255,255,0.6); font-size: 14px; margin-bottom: 6px; }

.footer-nav h4,
.footer-contact h4 { font-size: 15px; font-weight: 600; margin-bottom: 16px; color: #fff; }

.footer-nav ul li { margin-bottom: 8px; }
.footer-nav a { color: rgba(255,255,255,0.6); font-size: 14px; transition: color var(--transition); }
.footer-nav a:hover { color: #fff; }

.footer-contact p { color: rgba(255,255,255,0.6); font-size: 14px; margin-bottom: 8px; }

.footer-bottom {
  text-align: center;
  padding: 20px 0;
  color: rgba(255,255,255,0.4);
  font-size: 13px;
  line-height: 1.8;
}

/* ---- INNER PAGE HERO ---- */
.page-hero {
  background: linear-gradient(135deg, var(--primary) 0%, #0a3d8f 100%);
  padding: 60px 0;
  text-align: center;
  color: #fff;
}

.page-hero h1 { font-size: clamp(24px, 4vw, 42px); font-weight: 700; margin-bottom: 12px; }
.page-hero p { font-size: 16px; opacity: 0.8; }

/* ---- BREADCRUMB ---- */
.breadcrumb {
  padding: 12px 0;
  font-size: 13px;
  color: var(--text-light);
  border-bottom: 1px solid var(--border);
}
.breadcrumb a { color: var(--accent); }
.breadcrumb span { margin: 0 6px; }

/* ---- INNER CONTENT ---- */
.inner-content { padding: 60px 0; }
.inner-content h2 { font-size: 26px; margin-bottom: 16px; }
.inner-content p { color: var(--text-light); margin-bottom: 16px; font-size: 15px; }

/* ---- NEWS LIST ---- */
.news-list { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 28px; }

.news-card {
  background: var(--bg);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  transition: transform var(--transition);
}
.news-card:hover { transform: translateY(-4px); }
.news-card img { width: 100%; height: 180px; object-fit: cover; }
.news-card-body { padding: 20px; }
.news-card h3 { font-size: 16px; margin-bottom: 8px; font-weight: 600; }
.news-card p { font-size: 13px; color: var(--text-light); margin-bottom: 12px; }
.news-card .news-meta { font-size: 12px; color: var(--text-light); }

/* ---- RESPONSIVE ---- */
@media (max-width: 1024px) {
  .footer-top { grid-template-columns: 1fr 1fr; }
  .intro-grid { grid-template-columns: 1fr; gap: 40px; }
  .contact-grid { grid-template-columns: 1fr; gap: 40px; }
}

@media (max-width: 768px) {
  .header-inner { flex-wrap: wrap; }
  .nav { display: none; width: 100%; order: 3; }
  .nav.open { display: block; }
  .nav ul { flex-direction: column; gap: 0; padding: 10px 0; }
  .nav a { display: block; padding: 10px 0; border-bottom: 1px solid var(--border); }
  .nav-toggle { display: block; }
  .hero { min-height: 380px; }
  .hero-content { padding: 60px 24px; }
  .footer-top { grid-template-columns: 1fr; gap: 28px; }
  .stats-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 480px) {
  .video-grid { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: 1fr 1fr; gap: 24px; }
  .hero-btns { flex-direction: column; align-items: center; }
}