/* ============================================
   快手黑料 - 品牌影视传媒与视频社区网站
   原创CSS样式表 | 响应式设计 | 性能优化
   ============================================ */

:root {
  --primary-color: #0d5a7a;
  --secondary-color: #ff8c42;
  --accent-color: #00d4ff;
  --dark-bg: #0a0e27;
  --light-bg: #f5f7fa;
  --text-dark: #1a1a2e;
  --text-light: #ffffff;
  --border-color: #e0e0e0;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.2);
  --transition: all 0.3s ease;
}

/* ============================================
   全局样式
   ============================================ */

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

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Microsoft YaHei', 'PingFang SC', sans-serif;
  line-height: 1.6;
  color: var(--text-dark);
  background-color: var(--light-bg);
  overflow-x: hidden;
}

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

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

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

/* ============================================
   头部导航栏
   ============================================ */

header {
  background: linear-gradient(135deg, var(--primary-color) 0%, #0a3a52 100%);
  color: var(--text-light);
  padding: 0;
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: var(--shadow-md);
}

.header-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 20px;
  max-width: 1400px;
  margin: 0 auto;
  width: 100%;
}

.logo-container {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 18px;
  font-weight: bold;
  letter-spacing: 1px;
}

.logo-icon {
  width: 40px;
  height: 40px;
  border-radius: 8px;
  background: var(--secondary-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  color: var(--text-light);
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: 30px;
  align-items: center;
}

.nav-menu a {
  color: var(--text-light);
  font-weight: 500;
  position: relative;
  padding-bottom: 5px;
}

.nav-menu a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--secondary-color);
  transition: width 0.3s ease;
}

.nav-menu a:hover::after {
  width: 100%;
}

.search-box {
  position: relative;
  width: 200px;
}

.search-box input {
  width: 100%;
  padding: 8px 15px;
  border: none;
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.2);
  color: var(--text-light);
  font-size: 14px;
  outline: none;
  transition: var(--transition);
}

.search-box input::placeholder {
  color: rgba(255, 255, 255, 0.7);
}

.search-box input:focus {
  background: rgba(255, 255, 255, 0.3);
  box-shadow: 0 0 0 2px var(--secondary-color);
}

/* ============================================
   英雄区域 (Hero Section)
   ============================================ */

.hero {
  background: linear-gradient(135deg, rgba(13, 90, 122, 0.9) 0%, rgba(10, 58, 82, 0.9) 100%), 
              url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1200 600"><defs><pattern id="grid" width="40" height="40" patternUnits="userSpaceOnUse"><path d="M 40 0 L 0 0 0 40" fill="none" stroke="rgba(255,255,255,0.05)" stroke-width="1"/></pattern></defs><rect width="1200" height="600" fill="url(%23grid)"/></svg>');
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
  color: var(--text-light);
  padding: 80px 20px;
  text-align: center;
  position: relative;
  overflow: hidden;
  min-height: 500px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: radial-gradient(circle at 20% 50%, rgba(0, 212, 255, 0.1) 0%, transparent 50%),
              radial-gradient(circle at 80% 80%, rgba(255, 140, 66, 0.1) 0%, transparent 50%);
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 900px;
}

.hero h1 {
  font-size: 48px;
  font-weight: 700;
  margin-bottom: 20px;
  line-height: 1.2;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.hero-subtitle {
  font-size: 20px;
  margin-bottom: 30px;
  color: rgba(255, 255, 255, 0.9);
  font-weight: 300;
}

.hero-cta {
  display: flex;
  gap: 15px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  padding: 12px 30px;
  border-radius: 25px;
  font-size: 16px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: var(--transition);
  display: inline-block;
  text-align: center;
}

.btn-primary {
  background: var(--secondary-color);
  color: var(--text-light);
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  background: #ff7a1f;
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-secondary {
  background: transparent;
  color: var(--text-light);
  border: 2px solid var(--text-light);
}

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

/* ============================================
   内容区域 - 模块化布局
   ============================================ */

.section {
  padding: 60px 20px;
  max-width: 1400px;
  margin: 0 auto;
}

.section-title {
  font-size: 36px;
  font-weight: 700;
  margin-bottom: 15px;
  color: var(--text-dark);
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -10px;
  left: 0;
  width: 60px;
  height: 4px;
  background: linear-gradient(90deg, var(--secondary-color), var(--accent-color));
  border-radius: 2px;
}

.section-subtitle {
  font-size: 16px;
  color: #666;
  margin-bottom: 40px;
  line-height: 1.6;
}

/* ============================================
   视频卡片 - 核心功能
   ============================================ */

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 25px;
  margin-top: 40px;
}

.video-card {
  background: var(--text-light);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  cursor: pointer;
  position: relative;
}

.video-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
}

.video-thumbnail {
  position: relative;
  width: 100%;
  padding-bottom: 56.25%;
  overflow: hidden;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.video-thumbnail img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: var(--transition);
}

.video-card:hover .video-thumbnail img {
  transform: scale(1.05);
}

.play-button {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 60px;
  height: 60px;
  background: rgba(255, 140, 66, 0.9);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-light);
  font-size: 28px;
  opacity: 0;
  transition: var(--transition);
  z-index: 10;
}

.video-card:hover .play-button {
  opacity: 1;
}

.video-info {
  padding: 20px;
}

.video-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-dark);
  margin-bottom: 10px;
  line-height: 1.4;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.video-meta {
  display: flex;
  justify-content: space-between;
  font-size: 13px;
  color: #999;
  margin-bottom: 12px;
}

.video-stats {
  display: flex;
  gap: 15px;
  font-size: 12px;
  color: #666;
}

.video-tags {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 10px;
}

.tag {
  display: inline-block;
  background: #f0f0f0;
  color: var(--primary-color);
  padding: 4px 10px;
  border-radius: 12px;
  font-size: 12px;
  font-weight: 500;
}

/* ============================================
   专家展示区
   ============================================ */

.expert-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 30px;
  margin-top: 40px;
}

.expert-card {
  background: var(--text-light);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  text-align: center;
}

.expert-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
}

.expert-image {
  width: 100%;
  height: 250px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  overflow: hidden;
}

.expert-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: var(--transition);
}

.expert-card:hover .expert-image img {
  transform: scale(1.05);
}

.expert-info {
  padding: 20px;
}

.expert-name {
  font-size: 18px;
  font-weight: 700;
  color: var(--text-dark);
  margin-bottom: 5px;
}

.expert-title {
  font-size: 14px;
  color: var(--secondary-color);
  font-weight: 600;
  margin-bottom: 10px;
}

.expert-desc {
  font-size: 13px;
  color: #666;
  line-height: 1.5;
  margin-bottom: 15px;
}

.expert-actions {
  display: flex;
  gap: 10px;
  justify-content: center;
}

.expert-actions a {
  padding: 8px 15px;
  background: var(--primary-color);
  color: var(--text-light);
  border-radius: 15px;
  font-size: 12px;
  font-weight: 600;
  transition: var(--transition);
}

.expert-actions a:hover {
  background: var(--secondary-color);
}

/* ============================================
   FAQ区域
   ============================================ */

.faq-container {
  max-width: 800px;
  margin: 40px auto;
}

.faq-item {
  background: var(--text-light);
  border-left: 4px solid var(--secondary-color);
  border-radius: 8px;
  margin-bottom: 15px;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

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

.faq-question {
  padding: 20px;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 600;
  color: var(--text-dark);
  user-select: none;
  transition: var(--transition);
}

.faq-question:hover {
  background: #f9f9f9;
}

.faq-toggle {
  font-size: 20px;
  transition: transform 0.3s ease;
}

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

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
  padding: 0 20px;
}

.faq-item.active .faq-answer {
  max-height: 500px;
  padding: 0 20px 20px 20px;
}

.faq-answer p {
  color: #666;
  line-height: 1.6;
  font-size: 14px;
}

/* ============================================
   用户评论区
   ============================================ */

.reviews-container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 25px;
  margin-top: 40px;
}

.review-card {
  background: var(--text-light);
  padding: 25px;
  border-radius: 12px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  border-top: 3px solid var(--secondary-color);
}

.review-card:hover {
  box-shadow: var(--shadow-md);
}

.review-header {
  display: flex;
  align-items: center;
  margin-bottom: 15px;
}

.review-avatar {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-light);
  font-weight: bold;
  font-size: 20px;
  margin-right: 15px;
}

.review-avatar-img {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  object-fit: cover;
  margin-right: 15px;
  border: 2px solid var(--secondary-color);
  box-shadow: var(--shadow-sm);
}

.review-author {
  flex: 1;
}

.review-name {
  font-weight: 600;
  color: var(--text-dark);
  font-size: 15px;
}

.review-role {
  font-size: 12px;
  color: #999;
}

.review-rating {
  color: #ffc107;
  font-size: 14px;
  margin-bottom: 10px;
}

.review-text {
  color: #666;
  font-size: 14px;
  line-height: 1.6;
  font-style: italic;
}

/* ============================================
   合作品牌区
   ============================================ */

.brands-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 20px;
  margin-top: 40px;
  align-items: center;
  justify-items: center;
}

.brand-logo {
  width: 120px;
  height: 80px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--text-light);
  border-radius: 8px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  cursor: pointer;
}

.brand-logo:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-md);
}

.brand-logo img {
  max-width: 90%;
  max-height: 70%;
  object-fit: contain;
}

/* ============================================
   页脚
   ============================================ */

footer {
  background: var(--text-dark);
  color: var(--text-light);
  padding: 50px 20px 20px;
  margin-top: 80px;
}

.footer-content {
  max-width: 1400px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 40px;
  margin-bottom: 40px;
}

.footer-section h3 {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 20px;
  color: var(--secondary-color);
}

.footer-section ul {
  list-style: none;
}

.footer-section ul li {
  margin-bottom: 12px;
}

.footer-section a {
  color: rgba(255, 255, 255, 0.7);
  font-size: 14px;
  transition: var(--transition);
}

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

.footer-contact {
  font-size: 14px;
  line-height: 1.8;
  color: rgba(255, 255, 255, 0.7);
}

.footer-qr {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 15px;
}

.qr-code {
  width: 120px;
  height: 120px;
  background: var(--text-light);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  color: #999;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 20px;
  text-align: center;
  font-size: 13px;
  color: rgba(255, 255, 255, 0.6);
}

.update-time {
  color: var(--secondary-color);
  font-weight: 600;
}

/* ============================================
   社交分享
   ============================================ */

.social-share {
  display: flex;
  gap: 10px;
  margin-top: 15px;
}

.share-btn {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  transition: var(--transition);
  cursor: pointer;
  color: var(--text-light);
}

.share-wechat {
  background: #09b83e;
}

.share-weibo {
  background: #e6162d;
}

.share-douyin {
  background: #000000;
}

.share-bilibili {
  background: #fb7299;
}

.share-btn:hover {
  transform: scale(1.1);
  opacity: 0.8;
}

/* ============================================
   响应式设计 - 平板设备
   ============================================ */

@media (max-width: 768px) {
  :root {
    font-size: 14px;
  }

  .header-top {
    flex-wrap: wrap;
    gap: 15px;
  }

  .nav-menu {
    gap: 15px;
    font-size: 14px;
  }

  .search-box {
    width: 100%;
    order: 3;
  }

  .hero {
    padding: 50px 15px;
    min-height: 350px;
  }

  .hero h1 {
    font-size: 32px;
  }

  .hero-subtitle {
    font-size: 16px;
  }

  .section {
    padding: 40px 15px;
  }

  .section-title {
    font-size: 28px;
  }

  .video-grid {
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 15px;
  }

  .expert-grid {
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 20px;
  }

  .footer-content {
    grid-template-columns: 1fr;
    gap: 30px;
  }
}

/* ============================================
   响应式设计 - 手机设备
   ============================================ */

@media (max-width: 480px) {
  :root {
    font-size: 13px;
  }

  .header-top {
    padding: 10px 15px;
  }

  .logo-container {
    gap: 8px;
    font-size: 16px;
  }

  .logo-icon {
    width: 35px;
    height: 35px;
    font-size: 20px;
  }

  .nav-menu {
    display: none;
  }

  .search-box {
    width: 100%;
  }

  .hero {
    padding: 40px 15px;
    min-height: 300px;
  }

  .hero h1 {
    font-size: 24px;
  }

  .hero-subtitle {
    font-size: 14px;
  }

  .hero-cta {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }

  .section {
    padding: 30px 15px;
  }

  .section-title {
    font-size: 22px;
  }

  .video-grid {
    grid-template-columns: 1fr;
    gap: 15px;
  }

  .expert-grid {
    grid-template-columns: 1fr;
    gap: 15px;
  }

  .expert-image {
    height: 200px;
  }

  .reviews-container {
    grid-template-columns: 1fr;
  }

  .footer-content {
    grid-template-columns: 1fr;
    gap: 25px;
  }

  .faq-question {
    padding: 15px;
    font-size: 14px;
  }

  .faq-answer {
    padding: 0 15px;
  }

  .faq-item.active .faq-answer {
    padding: 0 15px 15px 15px;
  }
}

/* ============================================
   懒加载占位符
   ============================================ */

.lazy-placeholder {
  background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
  background-size: 200% 100%;
  animation: loading 1.5s infinite;
}

@keyframes loading {
  0% {
    background-position: 200% 0;
  }
  100% {
    background-position: -200% 0;
  }
}

/* ============================================
   动画效果
   ============================================ */

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slideInLeft {
  from {
    opacity: 0;
    transform: translateX(-30px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

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

.slide-in-left {
  animation: slideInLeft 0.6s ease-out;
}

/* ============================================
   工具类
   ============================================ */

.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 20px;
}

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

.text-right {
  text-align: right;
}

.mt-20 {
  margin-top: 20px;
}

.mb-20 {
  margin-bottom: 20px;
}

.hidden {
  display: none !important;
}

.visible {
  display: block !important;
}