```css
/* ============================================
   芒果传媒 - 全局样式
   设计语言: 影视质感 · 优雅 · 专业
   ============================================ */

/* ---------- CSS 变量 ---------- */
:root {
  /* 主色板 - 深蓝影视调 */
  --brand-primary: #1e4b6e;
  --brand-secondary: #b45309;
  --brand-gradient-start: #0a2a3e;
  --brand-gradient-end: #1e4b6e;
  --brand-accent: #fbbf24;

  /* 背景 */
  --bg-body: #ffffff;
  --bg-soft: #f5f8fc;
  --bg-card: #ffffff;
  --bg-navbar: rgba(255, 255, 255, 0.85);
  --bg-banner: linear-gradient(135deg, #0a2a3e 0%, #1e4b6e 100%);
  --bg-footer: #0d1b2a;
  --bg-svg: #f5f8fc;

  /* 文字 */
  --text-primary: #1f2937;
  --text-secondary: #2c3e50;
  --text-title: #0f172a;
  --text-muted: #4b5563;
  --text-on-dark: #e2e8f0;
  --text-link: #1d4ed8;

  /* 边框 */
  --border-light: #e2e8f0;
  --border-dark: #334155;

  /* 阴影 */
  --shadow-card: 0 4px 12px rgba(0, 0, 0, 0.04);
  --shadow-hover: 0 8px 24px rgba(30, 75, 110, 0.12);

  /* 圆角 */
  --radius-lg: 24px;
  --radius-md: 18px;
  --radius-sm: 12px;
  --radius-pill: 40px;

  /* 字体 */
  --font-sans: system-ui, -apple-system, 'Segoe UI', Roboto, 'PingFang SC',
    'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;

  /* 导航高度 */
  --nav-height: 64px;
}

/* 暗色模式变量 */
[data-theme='dark'] {
  --bg-body: #111c28;
  --bg-soft: #1a2637;
  --bg-card: #1f2a3c;
  --bg-navbar: rgba(15, 23, 42, 0.9);
  --bg-footer: #0a101c;
  --bg-svg: #1a2637;

  --text-primary: #e2e8f0;
  --text-secondary: #cbd5e1;
  --text-title: #f8fafc;
  --text-muted: #9ca3af;
  --text-on-dark: #cbd5e1;
  --text-link: #93c5fd;

  --border-light: #334155;

  --shadow-card: 0 4px 12px rgba(0, 0, 0, 0.3);
  --shadow-hover: 0 8px 24px rgba(0, 0, 0, 0.4);
}

/* ---------- Reset & 基础 ---------- */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-body);
  color: var(--text-primary);
  line-height: 1.7;
  font-size: 16px;
  transition: background-color 0.3s ease, color 0.3s ease;
  overflow-x: hidden;
}

/* 容器 */
.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 20px;
}

/* 滚动条 */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-soft);
}

::-webkit-scrollbar-thumb {
  background: var(--brand-primary);
  border-radius: 10px;
}

::selection {
  background: var(--brand-primary);
  color: #fff;
}

/* ---------- 排版 ---------- */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-title);
  font-weight: 600;
  line-height: 1.3;
  margin: 0;
}

h1 {
  font-size: clamp(1.8rem, 4vw, 2.4rem);
  margin-bottom: 0.5rem;
  font-weight: 700;
}

h2 {
  font-size: clamp(1.5rem, 3vw, 2rem);
  margin: 2.5rem 0 1.5rem;
  position: relative;
  padding-bottom: 0.5rem;
}

h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60px;
  height: 4px;
  background: var(--brand-gradient-start);
  border-radius: 4px;
}

[data-theme='dark'] h2::after {
  background: var(--brand-accent);
}

h3 {
  font-size: 1.35rem;
  margin: 1rem 0 0.75rem;
}

h4 {
  font-size: 1.1rem;
  margin: 0.75rem 0 0.5rem;
}

p {
  color: var(--text-primary);
  margin: 0.5rem 0;
}

a {
  color: var(--text-link);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  text-decoration: underline;
  color: var(--brand-primary);
}

/* ---------- 导航栏 ---------- */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--bg-navbar);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--border-light);
  transition: background 0.3s ease, box-shadow 0.3s ease;
  min-height: var(--nav-height);
  display: flex;
  align-items: center;
}

.navbar.scrolled {
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
  gap: 1rem;
}

.logo {
  font-weight: 700;
  font-size: 1.5rem;
  color: var(--text-title);
  white-space: nowrap;
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.logo span {
  color: var(--brand-primary);
}

[data-theme='dark'] .logo span {
  color: var(--brand-accent);
}

.nav-links {
  display: flex;
  gap: 1.5rem;
  align-items: center;
  flex-wrap: wrap;
}

.nav-links a {
  color: var(--text-primary);
  font-weight: 500;
  font-size: 0.95rem;
  position: relative;
  padding: 0.25rem 0;
}

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

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

.nav-links a:hover {
  color: var(--brand-primary);
  text-decoration: none;
}

/* 搜索框 */
.search-box {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.search-box input {
  padding: 0.5rem 1.25rem;
  border-radius: var(--radius-pill);
  border: 1px solid var(--border-light);
  background-color: var(--bg-soft);
  color: var(--text-primary);
  font-size: 0.9rem;
  width: 180px;
  transition: all 0.3s ease;
  outline: none;
}

.search-box input:focus {
  border-color: var(--brand-primary);
  box-shadow: 0 0 0 3px rgba(30, 75, 110, 0.1);
  width: 220px;
}

.search-box button {
  background: var(--brand-primary);
  border: none;
  color: white;
  padding: 0.5rem 1.25rem;
  border-radius: var(--radius-pill);
  cursor: pointer;
  font-weight: 500;
  font-size: 0.9rem;
  transition: background 0.2s ease, transform 0.2s ease;
}

.search-box button:hover {
  background: var(--brand-gradient-end);
  transform: scale(1.02);
}

/* 主题与菜单按钮 */
.theme-toggle,
.menu-toggle {
  background: transparent;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-pill);
  padding: 0.4rem 1rem;
  cursor: pointer;
  color: var(--text-primary);
  font-size: 0.9rem;
  transition: all 0.2s ease;
  white-space: nowrap;
}

.theme-toggle:hover,
.menu-toggle:hover {
  background: var(--bg-soft);
  border-color: var(--brand-primary);
}

.menu-toggle {
  display: none;
  font-size: 1.2rem;
  padding: 0.3rem 0.8rem;
}

/* ---------- 按钮 ---------- */
.btn {
  background-color: var(--brand-primary);
  color: #fff;
  padding: 0.75rem 2rem;
  border-radius: var(--radius-pill);
  border: none;
  cursor: pointer;
  font-weight: 500;
  display: inline-block;
  text-align: center;
  transition: all 0.3s ease;
  font-size: 0.95rem;
  letter-spacing: 0.02em;
  box-shadow: 0 4px 12px rgba(30, 75, 110, 0.2);
}

.btn:hover {
  background: var(--brand-gradient-end);
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(30, 75, 110, 0.3);
  text-decoration: none;
  color: #fff;
}

.btn:active {
  transform: translateY(0);
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--brand-primary);
  color: var(--brand-primary);
  box-shadow: none;
}

.btn-outline:hover {
  background: var(--brand-primary);
  color: #fff;
}

.banner .btn-outline {
  border-color: rgba(255, 255, 255, 0.8);
  color: rgba(255, 255, 255, 0.9);
}

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

/* ---------- 卡片 ---------- */
.card {
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: 2rem;
  box-shadow: var(--shadow-card);
  border: 1px solid var(--border-light);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--brand-primary), var(--brand-accent));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.4s ease;
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
}

.card:hover::before {
  transform: scaleX(1);
}

.card h3, .card h4 {
  margin-top: 0;
  position: relative;
}

/* 网格布局 */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.8rem;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
}

/* ---------- 横幅 (Banner) ---------- */
.banner {
  background: var(--bg-banner);
  border-radius: var(--radius-lg);
  padding: 4rem 3rem;
  color: #fff;
  margin: 2rem 0 3rem;
  position: relative;
  overflow: hidden;
  box-shadow: 0 20px 40px rgba(10, 42, 62, 0.3);
}

.banner::before {
  content: '';
  position: absolute;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
  top: -100px;
  right: -100px;
  border-radius: 50%;
}

.banner::after {
  content: '';
  position: absolute;
  width: 300px;
  height: 300px;
  background: radial-gradient(circle, rgba(251, 191, 36, 0.15) 0%, transparent 70%);
  bottom: -80px;
  left: -80px;
  border-radius: 50%;
}

.banner h1,
.banner p {
  color: #fff;
  position: relative;
  z-index: 2;
}

.banner h1 {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 700;
  text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

.banner p {
  font-size: 1.15rem;
  opacity: 0.9;
  max-width: 600px;
}

.banner .btn {
  background: var(--brand-accent);
  color: #0f172a;
  box-shadow: 0 4px 15px rgba(251, 191, 36, 0.3);
  position: relative;
  z-index: 2;
}

.banner .btn:hover {
  background: #fbbf24;
  box-shadow: 0 8px 25px rgba(251, 191, 36, 0.4);
  transform: translateY(-3px);
}

/* ---------- 面包屑 ---------- */
.breadcrumb {
  background-color: var(--bg-soft);
  padding: 0.5rem 1.25rem;
  border-radius: var(--radius-pill);
  margin: 1rem 0;
  font-size: 0.9rem;
  color: var(--text-secondary);
  display: inline-block;
  border: 1px solid var(--border-light);
}

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

/* ---------- 特性列表 ---------- */
.features-list {
  background: var(--bg-soft);
  padding: 2rem;
  border-radius: var(--radius-lg);
  margin-top: 2rem;
}

.features-list ul {
  columns: 2;
  list-style: none;
  padding-left: 0;
  margin: 0;
}

.features-list li {
  padding: 0.4rem 0;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  break-inside: avoid;
}

.features-list li::before {
  content: '✓';
  color: var(--brand-primary);
  font-weight: bold;
  font-size: 1.1rem;
  background: rgba(30, 75, 110, 0.1);
  width: 24px;
  height: 24px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

[data-theme='dark'] .features-list li::before {
  background: rgba(251, 191, 36, 0.15);
  color: var(--brand-accent);
}

/* ---------- FAQ ---------- */
.faq-item {
  border-bottom: 1px solid var(--border-light);
  padding: 1.2rem 0;
  transition: background 0.2s ease;
}

.faq-item:first-child {
  border-top: 1px solid var(--border-light);
}

.faq-question {
  font-weight: 600;
  color: var(--text-title);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 0.5rem 0;
  transition: color 0.2s ease;
  font-size: 1.05rem;
}

.faq-question::after {
  content: '+';
  font-size: 1.5rem;
  font-weight: 300;
  color: var(--brand-primary);
  transition: transform 0.3s ease;
  flex-shrink: 0;
}

.faq-question:hover {
  color: var(--brand-primary);
}

.faq-question.active::after {
  transform: rotate(45deg);
}

.faq-answer {
  margin-top: 0.75rem;
  color: var(--text-primary);
  padding-right: 2rem;
  line-height: 1.8;
}

/* ---------- 表格 ---------- */
.table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
}

.table th,
.table td {
  padding: 0.85rem 1rem;
  border: 1px solid var(--border-light);
  text-align: left;
}

.table th {
  background-color: var(--bg-soft);
  font-weight: 600;
  color: var(--text-title);
}

.table tr:hover td {
  background: var(--bg-soft);
}

/* ---------- 页脚 ---------- */
.footer {
  background-color: var(--bg-footer);
  color: var(--text-on-dark);
  margin-top: 4rem;
  padding: 3.5rem 0 2rem;
}

.footer h4 {
  color: #fff;
  font-size: 1.05rem;
  margin-bottom: 1rem;
  font-weight: 600;
}

.footer p {
  color: var(--text-on-dark);
  font-size: 0.9rem;
}

.footer a {
  color: #cbd5e1;
  font-size: 0.9rem;
  transition: color 0.2s ease;
}

.footer a:hover {
  color: #fff;
  text-decoration: none;
}

.footer .grid-4 {
  gap: 2rem;
}

.footer-bottom {
  border-top: 1px solid rgba(148, 163, 184, 0.2);
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: #94a3b8;
}

/* ---------- 返回顶部 ---------- */
.back-to-top {
  position: fixed;
  bottom: 25px;
  right: 25px;
  background: var(--brand-primary);
  color: #fff;
  padding: 0.75rem 1rem;
  border-radius: var(--radius-pill);
  cursor: pointer;
  border: none;
  z-index: 100;
  font-size: 1.2rem;
  box-shadow: 0 4px 15px rgba(30, 75, 110, 0.3);
  transition: all 0.3s ease;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--brand-gradient-end);
  transform: translateY(-3px);
}

/* ---------- 滚动动画 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.active {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- 辅助类 ---------- */
.text-secondary {
  color: var(--text-secondary);
}

.text-muted {
  color: var(--text-muted);
}

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

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mt-5 { margin-top: 3rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mb-5 { margin-bottom: 3rem; }

/* 隐藏元素 */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* 毛玻璃特殊卡片 */
.glass-card {
  background: rgba(255, 255, 255, 0.6);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: var(--radius-lg);
}

[data-theme='dark'] .glass-card {
  background: rgba(30, 42, 60, 0.6);
  border-color: rgba(255, 255, 255, 0.1);
}

/* ---------- 响应式 ---------- */
@media (max-width: 1024px) {
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .nav-links {
    gap: 1rem;
  }

  .search-box input {
    width: 140px;
  }
}

@media (max-width: 900px) {
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }

  .nav-links {
    display: none;
    width: 100%;
    flex-direction: column;
    align-items: flex-start;
    padding: 1rem 0;
    gap: 0.75rem;
  }

  .nav-links.open {
    display: flex;
  }

  .menu-toggle {
    display: inline-block;
    order: 2;
  }

  .nav-container {
    flex-wrap: wrap;
    padding: 0.75rem 1rem;
  }

  .nav-container > div:first-child {
    flex: 1;
  }

  .search-box {
    order: 3;
    width: 100%;
    margin-top: 0.5rem;
  }

  .search-box input {
    flex: 1;
    width: auto;
  }

  .search-box input:focus {
    width: auto;
  }

  .banner {
    padding: 2.5rem 1.5rem;
  }

  .banner h1 {
    font-size: 1.8rem;
  }

  .features-list ul {
    columns: 1;
  }
}

@media (max-width: 600px) {
  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .container {
    padding: 0 16px;
  }

  h1 {
    font-size: 1.6rem;
  }

  h2 {
    font-size: 1.4rem;
    margin: 1.5rem 0 1rem;
  }

  .card {
    padding: 1.5rem;
  }

  .banner {
    padding: 2rem 1.25rem;
    border-radius: var(--radius-md);
  }

  .banner .btn-group {
    flex-direction: column;
    gap: 0.75rem;
  }

  .banner .btn {
    width: 100%;
  }

  .theme-toggle {
    font-size: 0.75rem;
    padding: 0.3rem 0.6rem;
  }

  .footer .grid-4 {
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
  }

  .footer-bottom {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .back-to-top {
    bottom: 15px;
    right: 15px;
    padding: 0.6rem 0.8rem;
  }

  .breadcrumb {
    font-size: 0.8rem;
    padding: 0.4rem 1rem;
  }
}

/* 打印样式 */
@media print {
  .navbar,
  .back-to-top,
  .theme-toggle,
  .menu-toggle,
  .search-box,
  .footer {
    display: none !important;
  }

  body {
    font-size: 12pt;
    color: #000;
  }

  .card {
    box-shadow: none;
    border: 1px solid #ddd;
  }
}

/* 性能优化：减少重绘 */
* {
  -webkit-tap-highlight-color: transparent;
}

/* 焦点可见性 */
:focus-visible {
  outline: 3px solid var(--brand-accent);
  outline-offset: 2px;
}

/* 动画性能优化 */
.card,
.btn,
.banner,
.navbar {
  will-change: transform;
}
```