/* ============================================
   杏tv直播 原创样式表
   品牌：杏tv直播 | 域名：lqfilm.cn
   配色：糖心粉红 + 影视深紫 + 创意暖橙
   ============================================ */

/* CSS Variables */
:root {
  --tx-pink: #E8436F;
  --tx-pink-light: #F06292;
  --tx-pink-dark: #C62855;
  --tx-purple: #2D1B69;
  --tx-purple-deep: #1A0E2E;
  --tx-purple-light: #4A2D8F;
  --tx-orange: #FF8C42;
  --tx-orange-light: #FFB074;
  --tx-bg-light: #FFF5F7;
  --tx-bg-white: #FFFFFF;
  --tx-text-dark: #2C2C2C;
  --tx-text-gray: #666666;
  --tx-text-light: #F8E8EE;
  --tx-border: #F0D4DC;
  --tx-shadow: rgba(232, 67, 111, 0.15);
  --tx-gradient: linear-gradient(135deg, var(--tx-pink) 0%, var(--tx-purple) 100%);
  --tx-gradient-warm: linear-gradient(135deg, var(--tx-orange) 0%, var(--tx-pink) 100%);
  --tx-radius: 12px;
  --tx-radius-lg: 20px;
  --tx-transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* 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, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--tx-text-dark);
  background: var(--tx-bg-light);
  line-height: 1.7;
  overflow-x: hidden;
}
a { color: var(--tx-pink); text-decoration: none; transition: var(--tx-transition); }
a:hover { color: var(--tx-pink-dark); }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
.section-padding { padding: 80px 0; }

/* ============ Header / Navigation ============ */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: rgba(26, 14, 46, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(232, 67, 111, 0.2);
  transition: var(--tx-transition);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}
.site-logo { display: flex; align-items: center; gap: 10px; }
.site-logo img { height: 42px; width: auto; }
.site-logo span {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--tx-text-light);
  letter-spacing: 1px;
}
.main-nav { display: flex; align-items: center; gap: 6px; }
.main-nav a {
  color: var(--tx-text-light);
  font-size: 0.9rem;
  padding: 8px 14px;
  border-radius: 8px;
  transition: var(--tx-transition);
  white-space: nowrap;
}
.main-nav a:hover, .main-nav a.active {
  background: var(--tx-pink);
  color: #fff;
}
.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  color: var(--tx-text-light);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 8px;
}

/* Search Bar */
.search-bar-wrap {
  background: var(--tx-purple-deep);
  padding: 12px 0;
  margin-top: 70px;
  border-bottom: 1px solid rgba(232, 67, 111, 0.15);
}
.search-bar {
  display: flex;
  max-width: 600px;
  margin: 0 auto;
  position: relative;
}
.search-bar input {
  flex: 1;
  padding: 10px 20px;
  border: 2px solid var(--tx-pink);
  border-radius: 25px 0 0 25px;
  background: rgba(255,255,255,0.08);
  color: var(--tx-text-light);
  font-size: 0.95rem;
  outline: none;
  transition: var(--tx-transition);
}
.search-bar input::placeholder { color: rgba(248, 232, 238, 0.5); }
.search-bar input:focus { background: rgba(255,255,255,0.15); border-color: var(--tx-orange); }
.search-bar button {
  padding: 10px 24px;
  background: var(--tx-gradient);
  color: #fff;
  border: none;
  border-radius: 0 25px 25px 0;
  cursor: pointer;
  font-size: 0.95rem;
  transition: var(--tx-transition);
}
.search-bar button:hover { opacity: 0.9; }

/* ============ Banner / Hero ============ */
.hero-banner {
  position: relative;
  min-height: 600px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  background: var(--tx-purple-deep);
}
.hero-banner .hero-bg {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  object-fit: cover;
  opacity: 0.6;
}
.hero-banner .hero-overlay {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background: linear-gradient(180deg, rgba(26,14,46,0.7) 0%, rgba(232,67,111,0.3) 50%, rgba(26,14,46,0.8) 100%);
}
.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 40px 20px;
  max-width: 800px;
}
.hero-content h1 {
  font-size: 3rem;
  color: #fff;
  margin-bottom: 16px;
  text-shadow: 0 2px 20px rgba(232, 67, 111, 0.5);
  line-height: 1.3;
}
.hero-content h1 span { color: var(--tx-orange); }
.hero-content .hero-desc {
  font-size: 1.15rem;
  color: var(--tx-text-light);
  margin-bottom: 30px;
  line-height: 1.8;
}
.hero-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-bottom: 30px;
}
.hero-tags span {
  background: rgba(232, 67, 111, 0.25);
  color: var(--tx-text-light);
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 0.85rem;
  border: 1px solid rgba(232, 67, 111, 0.4);
}
.btn-primary {
  display: inline-block;
  padding: 14px 36px;
  background: var(--tx-gradient);
  color: #fff;
  border-radius: 30px;
  font-size: 1.05rem;
  font-weight: 600;
  transition: var(--tx-transition);
  border: none;
  cursor: pointer;
  box-shadow: 0 4px 20px var(--tx-shadow);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px var(--tx-shadow);
  color: #fff;
}
.btn-secondary {
  display: inline-block;
  padding: 12px 30px;
  background: transparent;
  color: var(--tx-text-light);
  border: 2px solid var(--tx-pink);
  border-radius: 30px;
  font-size: 1rem;
  transition: var(--tx-transition);
  cursor: pointer;
}
.btn-secondary:hover {
  background: var(--tx-pink);
  color: #fff;
}

/* ============ Section Titles ============ */
.section-title {
  text-align: center;
  margin-bottom: 50px;
}
.section-title h2 {
  font-size: 2rem;
  color: var(--tx-purple);
  margin-bottom: 12px;
  position: relative;
  display: inline-block;
}
.section-title h2::after {
  content: '';
  position: absolute;
  bottom: -8px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 3px;
  background: var(--tx-gradient);
  border-radius: 2px;
}
.section-title p {
  color: var(--tx-text-gray);
  font-size: 1rem;
  margin-top: 16px;
}

/* ============ Video Cards ============ */
.video-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.video-card {
  background: var(--tx-bg-white);
  border-radius: var(--tx-radius);
  overflow: hidden;
  box-shadow: 0 4px 16px rgba(0,0,0,0.06);
  transition: var(--tx-transition);
  position: relative;
}
.video-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 32px var(--tx-shadow);
}
.video-card .video-thumb {
  position: relative;
  padding-top: 56.25%;
  overflow: hidden;
}
.video-card .video-thumb img {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  object-fit: cover;
  transition: var(--tx-transition);
}
.video-card:hover .video-thumb img { transform: scale(1.05); }
.video-card .play-btn {
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%) scale(0.8);
  width: 56px; height: 56px;
  background: rgba(232, 67, 111, 0.9);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: var(--tx-transition);
  z-index: 2;
}
.video-card:hover .play-btn {
  opacity: 1;
  transform: translate(-50%, -50%) scale(1);
}
.play-btn::after {
  content: '';
  width: 0; height: 0;
  border-style: solid;
  border-width: 10px 0 10px 18px;
  border-color: transparent transparent transparent #fff;
  margin-left: 3px;
}
.video-card .video-duration {
  position: absolute;
  bottom: 8px; right: 8px;
  background: rgba(0,0,0,0.75);
  color: #fff;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.8rem;
  z-index: 2;
}
.video-card .video-info {
  padding: 14px 16px;
}
.video-card .video-info h3 {
  font-size: 0.95rem;
  color: var(--tx-text-dark);
  margin-bottom: 8px;
  line-height: 1.4;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.video-card .video-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.8rem;
  color: var(--tx-text-gray);
}
.video-card .video-meta span { display: flex; align-items: center; gap: 4px; }

/* ============ Star Cards ============ */
.star-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.star-card {
  background: var(--tx-bg-white);
  border-radius: var(--tx-radius);
  overflow: hidden;
  box-shadow: 0 4px 16px rgba(0,0,0,0.06);
  transition: var(--tx-transition);
  text-align: center;
}
.star-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 32px var(--tx-shadow);
}
.star-card .star-img {
  position: relative;
  padding-top: 130%;
  overflow: hidden;
}
.star-card .star-img img {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  object-fit: cover;
  transition: var(--tx-transition);
}
.star-card:hover .star-img img { transform: scale(1.05); }
.star-card .star-info { padding: 16px; }
.star-card .star-info h3 { font-size: 1.05rem; color: var(--tx-purple); margin-bottom: 6px; }
.star-card .star-info p { font-size: 0.85rem; color: var(--tx-text-gray); }

/* ============ Feature Modules ============ */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}
.feature-card {
  background: var(--tx-bg-white);
  border-radius: var(--tx-radius-lg);
  padding: 36px 28px;
  text-align: center;
  box-shadow: 0 4px 16px rgba(0,0,0,0.05);
  transition: var(--tx-transition);
  border: 1px solid var(--tx-border);
}
.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 32px var(--tx-shadow);
  border-color: var(--tx-pink);
}
.feature-card .feature-icon {
  width: 72px; height: 72px;
  margin: 0 auto 20px;
  background: var(--tx-gradient);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  color: #fff;
}
.feature-card h3 {
  font-size: 1.15rem;
  color: var(--tx-purple);
  margin-bottom: 10px;
}
.feature-card p {
  font-size: 0.9rem;
  color: var(--tx-text-gray);
  line-height: 1.7;
}

/* ============ Community Section ============ */
.community-section {
  background: var(--tx-purple-deep);
  color: var(--tx-text-light);
}
.community-section .section-title h2 { color: var(--tx-text-light); }
.community-section .section-title p { color: rgba(248, 232, 238, 0.7); }
.community-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}
.community-card {
  background: rgba(255,255,255,0.06);
  border-radius: var(--tx-radius-lg);
  padding: 30px;
  border: 1px solid rgba(232, 67, 111, 0.2);
  transition: var(--tx-transition);
}
.community-card:hover {
  background: rgba(255,255,255,0.1);
  border-color: var(--tx-pink);
}
.community-card h3 {
  font-size: 1.15rem;
  color: var(--tx-orange);
  margin-bottom: 10px;
}
.community-card p {
  font-size: 0.9rem;
  color: rgba(248, 232, 238, 0.8);
  line-height: 1.7;
}

/* ============ AI Section ============ */
.ai-section { background: linear-gradient(180deg, var(--tx-bg-light) 0%, #F0E6F6 100%); }
.ai-banner-img {
  width: 100%;
  border-radius: var(--tx-radius-lg);
  margin-bottom: 40px;
  box-shadow: 0 8px 32px rgba(45, 27, 105, 0.15);
}

/* ============ Expert Cards ============ */
.expert-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.expert-card {
  background: var(--tx-bg-white);
  border-radius: var(--tx-radius-lg);
  padding: 30px 20px;
  text-align: center;
  box-shadow: 0 4px 16px rgba(0,0,0,0.05);
  transition: var(--tx-transition);
  border: 1px solid var(--tx-border);
}
.expert-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 32px var(--tx-shadow);
}
.expert-card .expert-avatar {
  width: 100px; height: 100px;
  border-radius: 50%;
  object-fit: cover;
  margin: 0 auto 16px;
  border: 3px solid var(--tx-pink);
}
.expert-card h3 { font-size: 1.1rem; color: var(--tx-purple); margin-bottom: 4px; }
.expert-card .expert-title { font-size: 0.85rem; color: var(--tx-pink); margin-bottom: 10px; }
.expert-card p { font-size: 0.85rem; color: var(--tx-text-gray); line-height: 1.6; margin-bottom: 14px; }
.expert-card .expert-btns { display: flex; gap: 8px; justify-content: center; }
.expert-card .expert-btns a {
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 0.8rem;
  border: 1px solid var(--tx-pink);
  color: var(--tx-pink);
  transition: var(--tx-transition);
}
.expert-card .expert-btns a:hover { background: var(--tx-pink); color: #fff; }

/* ============ Reviews ============ */
.review-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}
.review-card {
  background: var(--tx-bg-white);
  border-radius: var(--tx-radius);
  padding: 24px;
  box-shadow: 0 4px 16px rgba(0,0,0,0.05);
  border-left: 4px solid var(--tx-pink);
}
.review-card .review-stars {
  color: var(--tx-orange);
  font-size: 1rem;
  margin-bottom: 10px;
}
.review-card .review-text {
  font-size: 0.95rem;
  color: var(--tx-text-dark);
  line-height: 1.7;
  margin-bottom: 12px;
  font-style: italic;
}
.review-card .review-author {
  font-size: 0.85rem;
  color: var(--tx-text-gray);
}
.review-card .review-author strong { color: var(--tx-purple); }

/* ============ FAQ ============ */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  background: var(--tx-bg-white);
  border-radius: var(--tx-radius);
  margin-bottom: 12px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
  overflow: hidden;
  border: 1px solid var(--tx-border);
}
.faq-question {
  padding: 18px 24px;
  font-size: 1rem;
  font-weight: 600;
  color: var(--tx-purple);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: var(--tx-transition);
}
.faq-question:hover { color: var(--tx-pink); }
.faq-question::after {
  content: '+';
  font-size: 1.3rem;
  color: var(--tx-pink);
  transition: var(--tx-transition);
}
.faq-item.active .faq-question::after { content: '-'; }
.faq-answer {
  padding: 0 24px;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  font-size: 0.9rem;
  color: var(--tx-text-gray);
  line-height: 1.7;
}
.faq-item.active .faq-answer {
  padding: 0 24px 18px;
  max-height: 300px;
}

/* ============ Partners ============ */
.partner-wall {
  width: 100%;
  border-radius: var(--tx-radius-lg);
  box-shadow: 0 4px 16px rgba(0,0,0,0.06);
}

/* ============ Contact Section ============ */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 40px;
  align-items: start;
}
.contact-info-card {
  background: var(--tx-bg-white);
  border-radius: var(--tx-radius-lg);
  padding: 36px;
  box-shadow: 0 4px 16px rgba(0,0,0,0.05);
}
.contact-info-card h3 {
  font-size: 1.2rem;
  color: var(--tx-purple);
  margin-bottom: 20px;
}
.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  margin-bottom: 16px;
  font-size: 0.95rem;
  color: var(--tx-text-dark);
}
.contact-item .contact-label {
  font-weight: 600;
  color: var(--tx-purple);
  min-width: 80px;
}
.qrcode-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}
.qrcode-item {
  text-align: center;
}
.qrcode-item img {
  width: 160px; height: 160px;
  margin: 0 auto 10px;
  border-radius: var(--tx-radius);
  border: 2px solid var(--tx-border);
}
.qrcode-item p {
  font-size: 0.85rem;
  color: var(--tx-text-gray);
}

/* ============ Footer ============ */
.site-footer {
  background: var(--tx-purple-deep);
  color: var(--tx-text-light);
  padding: 50px 0 20px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}
.footer-brand .footer-logo { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; }
.footer-brand .footer-logo img { height: 36px; }
.footer-brand .footer-logo span { font-size: 1.2rem; font-weight: 700; color: var(--tx-text-light); }
.footer-brand p { font-size: 0.9rem; color: rgba(248, 232, 238, 0.7); line-height: 1.7; }
.footer-col h4 {
  font-size: 1rem;
  color: var(--tx-text-light);
  margin-bottom: 16px;
  position: relative;
  padding-bottom: 10px;
}
.footer-col h4::after {
  content: '';
  position: absolute;
  bottom: 0; left: 0;
  width: 30px; height: 2px;
  background: var(--tx-pink);
}
.footer-col a {
  display: block;
  color: rgba(248, 232, 238, 0.7);
  font-size: 0.9rem;
  padding: 4px 0;
  transition: var(--tx-transition);
}
.footer-col a:hover { color: var(--tx-orange); padding-left: 4px; }
.footer-bottom {
  border-top: 1px solid rgba(232, 67, 111, 0.2);
  padding-top: 20px;
  text-align: center;
  font-size: 0.85rem;
  color: rgba(248, 232, 238, 0.5);
}
.footer-qr-row {
  display: flex;
  justify-content: center;
  gap: 40px;
  margin-bottom: 20px;
}
.footer-qr-item { text-align: center; }
.footer-qr-item img { width: 100px; height: 100px; border-radius: 8px; margin-bottom: 6px; }
.footer-qr-item p { font-size: 0.8rem; color: rgba(248, 232, 238, 0.6); }

/* ============ Social Share ============ */
.share-bar {
  display: flex;
  align-items: center;
  gap: 12px;
  justify-content: center;
  padding: 20px 0;
}
.share-bar span { font-size: 0.9rem; color: var(--tx-text-gray); }
.share-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px; height: 40px;
  border-radius: 50%;
  color: #fff;
  font-size: 0.9rem;
  transition: var(--tx-transition);
  cursor: pointer;
}
.share-btn:hover { transform: scale(1.1); color: #fff; }
.share-btn.wechat { background: #07C160; }
.share-btn.weibo { background: #E6162D; }
.share-btn.douyin { background: #161823; }
.share-btn.bilibili { background: #00A1D6; }

/* ============ Breadcrumb ============ */
.breadcrumb {
  padding: 14px 0;
  font-size: 0.85rem;
  color: var(--tx-text-gray);
  margin-top: 70px;
}
.breadcrumb a { color: var(--tx-pink); }
.breadcrumb a:hover { text-decoration: underline; }
.breadcrumb span { margin: 0 6px; }

/* ============ Inner Page Banner ============ */
.inner-banner {
  background: var(--tx-gradient);
  padding: 60px 0;
  text-align: center;
  margin-top: 70px;
}
.inner-banner h1 {
  font-size: 2.2rem;
  color: #fff;
  margin-bottom: 10px;
}
.inner-banner p {
  font-size: 1rem;
  color: var(--tx-text-light);
}

/* ============ Content Page ============ */
.content-wrap {
  padding: 50px 0;
}
.content-main {
  background: var(--tx-bg-white);
  border-radius: var(--tx-radius-lg);
  padding: 40px;
  box-shadow: 0 4px 16px rgba(0,0,0,0.05);
}
.content-main h2 {
  font-size: 1.5rem;
  color: var(--tx-purple);
  margin: 30px 0 16px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--tx-border);
}
.content-main h3 {
  font-size: 1.2rem;
  color: var(--tx-pink);
  margin: 24px 0 12px;
}
.content-main p {
  font-size: 0.95rem;
  color: var(--tx-text-dark);
  line-height: 1.8;
  margin-bottom: 16px;
}

/* ============ How-To Guide ============ */
.howto-steps {
  counter-reset: step;
}
.howto-step {
  display: flex;
  gap: 20px;
  margin-bottom: 28px;
  align-items: flex-start;
}
.howto-step::before {
  counter-increment: step;
  content: counter(step);
  flex-shrink: 0;
  width: 48px; height: 48px;
  background: var(--tx-gradient);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  font-weight: 700;
}
.howto-step-content h4 {
  font-size: 1.05rem;
  color: var(--tx-purple);
  margin-bottom: 6px;
}
.howto-step-content p {
  font-size: 0.9rem;
  color: var(--tx-text-gray);
}

/* ============ Tags ============ */
.tag-list { display: flex; flex-wrap: wrap; gap: 8px; margin: 16px 0; }
.tag {
  background: rgba(232, 67, 111, 0.1);
  color: var(--tx-pink);
  padding: 4px 14px;
  border-radius: 16px;
  font-size: 0.8rem;
  transition: var(--tx-transition);
}
.tag:hover { background: var(--tx-pink); color: #fff; }

/* ============ Lazy Load Placeholder ============ */
.lazy-img {
  background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}
@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* ============ Back to Top ============ */
.back-to-top {
  position: fixed;
  bottom: 30px; right: 30px;
  width: 46px; height: 46px;
  background: var(--tx-gradient);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: var(--tx-transition);
  z-index: 999;
  border: none;
  box-shadow: 0 4px 16px var(--tx-shadow);
}
.back-to-top.visible { opacity: 1; visibility: visible; }
.back-to-top:hover { transform: translateY(-3px); }

/* ============ Responsive ============ */
@media (max-width: 1024px) {
  .video-grid { grid-template-columns: repeat(3, 1fr); }
  .star-grid { grid-template-columns: repeat(3, 1fr); }
  .expert-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  .main-nav { display: none; }
  .main-nav.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 70px; left: 0;
    width: 100%;
    background: rgba(26, 14, 46, 0.98);
    padding: 20px;
    gap: 4px;
  }
  .mobile-menu-btn { display: block; }
  .hero-content h1 { font-size: 2rem; }
  .video-grid { grid-template-columns: repeat(2, 1fr); gap: 16px; }
  .star-grid { grid-template-columns: repeat(2, 1fr); gap: 16px; }
  .feature-grid { grid-template-columns: 1fr; }
  .community-grid { grid-template-columns: 1fr; }
  .review-grid { grid-template-columns: 1fr; }
  .expert-grid { grid-template-columns: repeat(2, 1fr); }
  .contact-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .section-padding { padding: 50px 0; }
  .content-main { padding: 24px; }
}
@media (max-width: 480px) {
  .video-grid { grid-template-columns: 1fr; }
  .star-grid { grid-template-columns: repeat(2, 1fr); }
  .expert-grid { grid-template-columns: 1fr; }
  .hero-content h1 { font-size: 1.6rem; }
  .hero-banner { min-height: 450px; }
}