/* ============================================
   51吃瓜 - 主样式文件
   ============================================ */

/* CSS变量 */
:root {
  --primary: #e8392a;
  --primary-dark: #c02a1d;
  --secondary: #ff6b35;
  --accent: #ffd700;
  --dark: #1a1a2e;
  --dark2: #16213e;
  --gray: #6c757d;
  --light-gray: #f8f9fa;
  --white: #ffffff;
  --border: #e9ecef;
  --shadow: 0 4px 20px rgba(0,0,0,0.08);
  --shadow-hover: 0 8px 30px rgba(232,57,42,0.15);
  --radius: 12px;
  --radius-sm: 8px;
  --transition: all 0.3s ease;
}

/* 重置 */
*, *::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", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: #333;
  background: #fff;
  line-height: 1.7;
  overflow-x: hidden;
}
a { color: var(--primary); text-decoration: none; transition: var(--transition); }
a:hover { color: var(--primary-dark); }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }

/* 容器 */
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
.section { padding: 80px 0; }
.section-alt { background: var(--light-gray); }
.section-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--dark);
  text-align: center;
  margin-bottom: 12px;
}
.section-subtitle {
  font-size: 1.05rem;
  color: var(--gray);
  text-align: center;
  margin-bottom: 50px;
}

/* ============ 头部导航 ============ */
.site-header {
  background: var(--white);
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
  position: sticky;
  top: 0;
  z-index: 1000;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary);
}
.logo-icon {
  width: 42px;
  height: 42px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 1.2rem;
  font-weight: 900;
}
.logo span { color: var(--dark); }

/* 导航菜单 */
.nav-menu { display: flex; align-items: center; gap: 8px; }
.nav-menu a {
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  color: #444;
  font-size: 0.95rem;
  font-weight: 500;
  transition: var(--transition);
}
.nav-menu a:hover, .nav-menu a.active {
  background: rgba(232,57,42,0.08);
  color: var(--primary);
}
.nav-cta {
  background: var(--primary) !important;
  color: var(--white) !important;
  padding: 8px 20px !important;
}
.nav-cta:hover { background: var(--primary-dark) !important; }

/* 汉堡菜单 */
.hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 5px; }
.hamburger span { display: block; width: 24px; height: 2px; background: #333; border-radius: 2px; transition: var(--transition); }

/* ============ 搜索框 ============ */
.search-bar-wrap {
  background: linear-gradient(90deg, var(--primary) 0%, var(--secondary) 100%);
  padding: 14px 0;
}
.search-bar-inner {
  display: flex;
  align-items: center;
  max-width: 700px;
  margin: 0 auto;
  background: #fff;
  border-radius: 40px;
  overflow: hidden;
  box-shadow: 0 4px 20px rgba(232,57,42,0.25);
}
.search-bar-inner input {
  flex: 1;
  border: none;
  outline: none;
  padding: 12px 20px;
  font-size: 1rem;
  color: #333;
  background: transparent;
}
.search-bar-inner button {
  background: var(--primary);
  border: none;
  color: #fff;
  padding: 12px 28px;
  font-size: 1rem;
  cursor: pointer;
  font-weight: 600;
  transition: var(--transition);
  border-radius: 0 40px 40px 0;
}
.search-bar-inner button:hover { background: var(--primary-dark); }

/* ============ Banner ============ */
.hero {
  position: relative;
  min-height: 520px;
  background: linear-gradient(135deg, var(--dark) 0%, var(--dark2) 100%);
  display: flex;
  align-items: center;
  overflow: hidden;
}
.hero-bg {
  position: absolute;
  inset: 0;
  background-image: url('../images/banner.jpg');
  background-size: cover;
  background-position: center;
  opacity: 0.3;
}
.hero-content {
  position: relative;
  z-index: 2;
  max-width: 680px;
}
.hero-badge {
  display: inline-block;
  background: rgba(255,215,0,0.15);
  border: 1px solid var(--accent);
  color: var(--accent);
  padding: 4px 14px;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 18px;
}
.hero h1 {
  font-size: 2.8rem;
  font-weight: 900;
  color: #fff;
  line-height: 1.25;
  margin-bottom: 18px;
}
.hero h1 em {
  font-style: normal;
  color: var(--accent);
}
.hero p {
  font-size: 1.1rem;
  color: rgba(255,255,255,0.85);
  margin-bottom: 32px;
  line-height: 1.8;
}
.hero-btns { display: flex; gap: 14px; flex-wrap: wrap; }
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 28px;
  border-radius: 40px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  text-decoration: none;
}
.btn-primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 4px 20px rgba(232,57,42,0.4);
}
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-2px); color: #fff; }
.btn-outline {
  background: transparent;
  border: 2px solid rgba(255,255,255,0.5);
  color: #fff;
}
.btn-outline:hover { border-color: #fff; background: rgba(255,255,255,0.1); color: #fff; }
.hero-stats {
  display: flex;
  gap: 32px;
  margin-top: 40px;
}
.hero-stat { text-align: center; }
.hero-stat .num { font-size: 1.8rem; font-weight: 800; color: var(--accent); }
.hero-stat .label { font-size: 0.85rem; color: rgba(255,255,255,0.7); }

/* ============ 功能模块 ============ */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 28px;
}
.feature-card {
  background: #fff;
  border-radius: var(--radius);
  padding: 32px 28px;
  box-shadow: var(--shadow);
  transition: var(--transition);
  border: 1px solid var(--border);
  text-align: center;
}
.feature-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
  border-color: var(--primary);
}
.feature-icon {
  width: 64px;
  height: 64px;
  background: linear-gradient(135deg, rgba(232,57,42,0.1), rgba(255,107,53,0.1));
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
  font-size: 1.8rem;
}
.feature-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 10px;
}
.feature-card p { color: var(--gray); font-size: 0.95rem; line-height: 1.7; }
.feature-img {
  width: 100%;
  height: 180px;
  object-fit: cover;
  border-radius: var(--radius-sm);
  margin-bottom: 18px;
}

/* ============ 视频区域 ============ */
.video-section { background: var(--dark); }
.video-section .section-title { color: #fff; }
.video-section .section-subtitle { color: rgba(255,255,255,0.7); }
.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}
.video-card {
  background: rgba(255,255,255,0.05);
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid rgba(255,255,255,0.1);
  transition: var(--transition);
  cursor: pointer;
}
.video-card:hover { transform: translateY(-4px); border-color: var(--primary); }
.video-thumb {
  position: relative;
  width: 100%;
  padding-top: 56.25%;
  overflow: hidden;
  background: #000;
}
.video-thumb img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: var(--transition);
}
.video-card:hover .video-thumb img { transform: scale(1.05); opacity: 0.8; }
.play-btn {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) scale(0);
  width: 56px;
  height: 56px;
  background: rgba(232,57,42,0.9);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  z-index: 2;
}
.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:hover .play-btn { transform: translate(-50%, -50%) scale(1); }
.video-duration {
  position: absolute;
  bottom: 8px;
  right: 10px;
  background: rgba(0,0,0,0.75);
  color: #fff;
  font-size: 0.8rem;
  padding: 2px 8px;
  border-radius: 4px;
}
.video-info { padding: 16px; }
.video-info h3 { color: #fff; font-size: 1rem; font-weight: 600; margin-bottom: 8px; line-height: 1.5; }
.video-meta { display: flex; gap: 14px; color: rgba(255,255,255,0.5); font-size: 0.85rem; }
.video-meta span { display: flex; align-items: center; gap: 4px; }

/* ============ 使用场景 ============ */
.scenarios-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
}
.scenario-card {
  background: #fff;
  border-radius: var(--radius);
  padding: 28px 22px;
  text-align: center;
  border: 1px solid var(--border);
  transition: var(--transition);
}
.scenario-card:hover { border-color: var(--primary); box-shadow: var(--shadow-hover); }
.scenario-icon { font-size: 2.5rem; margin-bottom: 14px; }
.scenario-card h3 { font-size: 1rem; font-weight: 700; color: var(--dark); margin-bottom: 8px; }
.scenario-card p { font-size: 0.9rem; color: var(--gray); }

/* ============ 教程步骤 ============ */
.steps-list { display: flex; flex-direction: column; gap: 24px; max-width: 800px; margin: 0 auto; }
.step-item { display: flex; gap: 20px; align-items: flex-start; }
.step-num {
  min-width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  font-weight: 800;
  flex-shrink: 0;
}
.step-content h3 { font-size: 1.1rem; font-weight: 700; color: var(--dark); margin-bottom: 6px; }
.step-content p { color: var(--gray); font-size: 0.95rem; }

/* ============ 更新日志 ============ */
.changelog-list { max-width: 800px; margin: 0 auto; }
.changelog-item {
  display: flex;
  gap: 20px;
  padding: 24px 0;
  border-bottom: 1px solid var(--border);
}
.changelog-item:last-child { border-bottom: none; }
.changelog-version {
  min-width: 90px;
  text-align: center;
}
.version-badge {
  display: inline-block;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: #fff;
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 700;
}
.changelog-date { font-size: 0.8rem; color: var(--gray); margin-top: 6px; }
.changelog-content h3 { font-size: 1rem; font-weight: 600; color: var(--dark); margin-bottom: 6px; }
.changelog-content p { color: var(--gray); font-size: 0.9rem; }

/* ============ FAQ ============ */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  margin-bottom: 12px;
  overflow: hidden;
}
.faq-question {
  padding: 18px 22px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  font-weight: 600;
  color: var(--dark);
  background: #fff;
  transition: var(--transition);
  user-select: none;
}
.faq-question:hover { background: rgba(232,57,42,0.04); color: var(--primary); }
.faq-question.active { color: var(--primary); background: rgba(232,57,42,0.04); }
.faq-arrow {
  font-size: 1.2rem;
  transition: var(--transition);
  color: var(--gray);
  flex-shrink: 0;
}
.faq-question.active .faq-arrow { transform: rotate(180deg); color: var(--primary); }
.faq-answer {
  display: none;
  padding: 0 22px 18px;
  color: var(--gray);
  font-size: 0.95rem;
  line-height: 1.8;
  background: rgba(232,57,42,0.02);
}
.faq-answer.open { display: block; }

/* ============ 用户评价 ============ */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}
.review-card {
  background: #fff;
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  transition: var(--transition);
}
.review-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-hover); }
.review-header { display: flex; align-items: center; gap: 14px; margin-bottom: 16px; }
.review-avatar {
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 1.2rem;
  font-weight: 700;
  flex-shrink: 0;
}
.review-user h4 { font-size: 1rem; font-weight: 700; color: var(--dark); }
.review-stars { color: var(--accent); font-size: 0.9rem; }
.review-text { color: var(--gray); font-size: 0.95rem; line-height: 1.7; }
.review-tag {
  display: inline-block;
  margin-top: 12px;
  background: rgba(232,57,42,0.08);
  color: var(--primary);
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 0.8rem;
}

/* ============ 联系我们 ============ */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 24px;
  max-width: 900px;
  margin: 0 auto;
}
.contact-card {
  background: #fff;
  border-radius: var(--radius);
  padding: 32px 24px;
  text-align: center;
  border: 1px solid var(--border);
  transition: var(--transition);
}
.contact-card:hover { border-color: var(--primary); box-shadow: var(--shadow-hover); }
.contact-icon { font-size: 2.5rem; margin-bottom: 14px; }
.contact-card h3 { font-size: 1rem; font-weight: 700; color: var(--dark); margin-bottom: 8px; }
.contact-card p { color: var(--gray); font-size: 0.9rem; }
.contact-card a { color: var(--primary); font-weight: 600; }

/* ============ 页脚 ============ */
.site-footer {
  background: var(--dark);
  color: rgba(255,255,255,0.7);
  padding: 60px 0 0;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}
.footer-brand .logo { color: #fff; margin-bottom: 14px; }
.footer-brand p { font-size: 0.9rem; line-height: 1.8; }
.footer-col h4 {
  color: #fff;
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 16px;
}
.footer-col ul { display: flex; flex-direction: column; gap: 10px; }
.footer-col ul li a { color: rgba(255,255,255,0.6); font-size: 0.9rem; }
.footer-col ul li a:hover { color: var(--primary); }
.footer-bottom {
  padding: 20px 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
  font-size: 0.85rem;
}
.footer-bottom a { color: rgba(255,255,255,0.5); }
.footer-bottom a:hover { color: var(--primary); }

/* ============ 内页通用 ============ */
.page-hero {
  background: linear-gradient(135deg, var(--dark) 0%, var(--dark2) 100%);
  padding: 60px 0;
  text-align: center;
}
.page-hero h1 { color: #fff; font-size: 2.2rem; font-weight: 800; margin-bottom: 12px; }
.page-hero p { color: rgba(255,255,255,0.75); font-size: 1.05rem; }
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9rem;
  color: rgba(255,255,255,0.5);
  justify-content: center;
  margin-top: 16px;
}
.breadcrumb a { color: rgba(255,255,255,0.7); }
.breadcrumb a:hover { color: #fff; }
.breadcrumb span { color: rgba(255,255,255,0.4); }

/* 标签 */
.tag {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  background: rgba(232,57,42,0.1);
  color: var(--primary);
  margin: 3px;
}

/* 卡片列表 */
.card-list { display: flex; flex-direction: column; gap: 20px; }
.card-item {
  background: #fff;
  border-radius: var(--radius);
  padding: 24px 28px;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  transition: var(--transition);
}
.card-item:hover { border-color: var(--primary); box-shadow: var(--shadow-hover); }
.card-item h3 { font-size: 1.1rem; font-weight: 700; color: var(--dark); margin-bottom: 8px; }
.card-item p { color: var(--gray); font-size: 0.95rem; }

/* 侧边栏布局 */
.content-layout {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 40px;
  align-items: start;
}
.sidebar-card {
  background: #fff;
  border-radius: var(--radius);
  padding: 24px;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  margin-bottom: 24px;
}
.sidebar-card h4 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--primary);
}
.sidebar-links { display: flex; flex-direction: column; gap: 10px; }
.sidebar-links a {
  color: #555;
  font-size: 0.9rem;
  padding: 6px 0;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 8px;
}
.sidebar-links a:hover { color: var(--primary); }

/* ============ 响应式 ============ */
@media (max-width: 1024px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .content-layout { grid-template-columns: 1fr; }
}
@media (max-width: 768px) {
  .section { padding: 60px 0; }
  .section-title { font-size: 1.6rem; }
  .hero h1 { font-size: 2rem; }
  .hero-stats { gap: 20px; }
  .hero-stat .num { font-size: 1.4rem; }
  .nav-menu { display: none; position: absolute; top: 70px; left: 0; right: 0; background: #fff; flex-direction: column; padding: 16px; box-shadow: 0 8px 20px rgba(0,0,0,0.1); gap: 4px; }
  .nav-menu.open { display: flex; }
  .hamburger { display: flex; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; text-align: center; }
  .features-grid { grid-template-columns: 1fr; }
  .video-grid { grid-template-columns: 1fr; }
}
@media (max-width: 480px) {
  .hero h1 { font-size: 1.6rem; }
  .hero-btns { flex-direction: column; }
  .btn { justify-content: center; }
  .hero-stats { flex-wrap: wrap; gap: 16px; }
}

/* ============ 工具类 ============ */
.text-center { text-align: center; }
.text-primary { color: var(--primary); }
.mt-4 { margin-top: 16px; }
.mt-8 { margin-top: 32px; }
.mb-4 { margin-bottom: 16px; }
.mb-8 { margin-bottom: 32px; }
.d-flex { display: flex; }
.align-center { align-items: center; }
.gap-2 { gap: 8px; }
.fw-bold { font-weight: 700; }

/* 滚动条 */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: #f1f1f1; }
::-webkit-scrollbar-thumb { background: var(--primary); border-radius: 3px; }

/* 视频模态框 */
.video-modal {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.85);
  z-index: 9999;
  align-items: center;
  justify-content: center;
}
.video-modal.open { display: flex; }
.video-modal-inner {
  background: #000;
  border-radius: var(--radius);
  overflow: hidden;
  width: 90%;
  max-width: 800px;
  position: relative;
}
.video-modal-close {
  position: absolute;
  top: 12px;
  right: 14px;
  background: rgba(255,255,255,0.2);
  border: none;
  color: #fff;
  font-size: 1.4rem;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2;
  transition: var(--transition);
}
.video-modal-close:hover { background: var(--primary); }
.video-placeholder {
  width: 100%;
  padding-top: 56.25%;
  position: relative;
  background: #111;
}
.video-placeholder-inner {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: rgba(255,255,255,0.6);
  font-size: 1rem;
}
.video-placeholder-inner .big-play {
  font-size: 4rem;
  color: var(--primary);
  margin-bottom: 12px;
}

/* 面包屑 */
.breadcrumb-bar {
  background: var(--light-gray);
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
}
.breadcrumb-bar .breadcrumb {
  justify-content: flex-start;
  color: var(--gray);
}
.breadcrumb-bar .breadcrumb a { color: var(--primary); }