/* roulang page: index */
/* ----- 设计变量 ----- */
    :root {
      --primary: #0AE0F0;
      --primary-dark: #0BBFC9;
      --secondary-dark: #0B1D3A;
      --accent: #FF5E3A;
      --accent-hover: #E04A2A;
      --bg-page: #F7F8FC;
      --card-bg: #FFFFFF;
      --text-main: #1F2937;
      --text-secondary: #4B5560;
      --text-tertiary: #6B7280;
      --border-light: #E5E7EB;
      --gradient-cta: linear-gradient(135deg, #0B1D3A 0%, #0AE0F0 100%);
      --shadow-card: 0 4px 24px rgba(11, 29, 58, 0.06);
      --shadow-card-hover: 0 12px 32px rgba(11, 29, 58, 0.12);
      --radius-card: 16px;
      --radius-btn: 50px;
      --radius-tag: 20px;
      --spacing-section: 80px;
      --max-width: 1280px;
      --nav-height: 72px;
    }

    /* ----- 基础重置 ----- */
    *, *::before, *::after {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    html {
      scroll-behavior: smooth;
      scroll-padding-top: var(--nav-height);
    }

    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Helvetica Neue", Arial, sans-serif;
      font-size: 16px;
      font-weight: 400;
      line-height: 1.7;
      color: var(--text-main);
      background-color: var(--bg-page);
      overflow-x: hidden;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease;
    }

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: transparent;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: all 0.3s ease;
      font-weight: 600;
      white-space: nowrap;
    }

    ul {
      list-style: none;
    }

    /* ----- 布局容器 ----- */
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 32px;
    }

    @media (max-width: 768px) {
      .container {
        padding: 0 16px;
      }
    }

    /* ----- 版块标题 ----- */
    .section-heading {
      text-align: center;
      margin-bottom: 60px;
    }

    .section-heading h2 {
      font-size: 36px;
      font-weight: 700;
      letter-spacing: -0.3px;
      color: var(--secondary-dark);
      margin-bottom: 12px;
    }

    .section-heading p {
      font-size: 16px;
      color: var(--text-tertiary);
      max-width: 700px;
      margin: 0 auto;
    }

    /* ----- 导航：白底平台导航 ----- */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background: rgba(255,255,255,0.96);
      backdrop-filter: blur(10px);
      box-shadow: 0 1px 0 var(--border-light);
      z-index: 100;
      display: flex;
      align-items: center;
    }

    .header-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }

    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-size: 22px;
      font-weight: 700;
      color: var(--secondary-dark);
    }

    .logo-icon {
      width: 32px;
      height: 32px;
      background: var(--primary);
      border-radius: 6px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--secondary-dark);
      font-weight: 900;
      font-size: 18px;
    }

    .logo-domain {
      font-size: 12px;
      font-weight: 400;
      color: var(--text-tertiary);
      margin-left: 4px;
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 40px;
    }

    .nav-menu a {
      font-size: 16px;
      font-weight: 500;
      color: var(--secondary-dark);
      position: relative;
      padding: 4px 0;
      transition: color 0.2s;
    }

    .nav-menu a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width 0.25s ease;
    }

    .nav-menu a:hover {
      color: var(--primary);
    }

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

    .btn-primary {
      background: var(--accent);
      color: white;
      border-radius: var(--radius-btn);
      padding: 14px 32px;
      font-weight: 600;
      font-size: 16px;
      box-shadow: 0 4px 12px rgba(255, 94, 58, 0.25);
    }

    .btn-primary:hover {
      background: var(--accent-hover);
      box-shadow: 0 6px 18px rgba(255, 94, 58, 0.4);
      transform: translateY(-2px);
    }

    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      border-radius: var(--radius-btn);
      padding: 12px 30px;
    }

    .btn-outline:hover {
      background: rgba(10, 224, 240, 0.08);
      border-color: #0BC4D6;
    }

    /* 汉堡菜单 */
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 6px;
      cursor: pointer;
      z-index: 120;
    }
    .hamburger span {
      width: 28px;
      height: 2px;
      background: var(--secondary-dark);
      transition: 0.3s;
    }
    .mobile-nav {
      display: none;
    }

    @media (max-width: 768px) {
      .nav-menu, .header-cta-desktop {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .mobile-nav {
        display: block;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: white;
        padding: 100px 32px 40px;
        transform: translateX(100%);
        transition: transform 0.35s ease;
        z-index: 110;
      }
      .mobile-nav.active {
        transform: translateX(0);
      }
      .mobile-nav a {
        display: block;
        font-size: 24px;
        font-weight: 600;
        margin-bottom: 32px;
        color: var(--secondary-dark);
      }
      .mobile-nav .btn-primary {
        width: fit-content;
      }
    }

    /* ----- 首屏 Hero 双栏 ----- */
    .hero {
      padding: calc(var(--nav-height) + 80px) 0 80px;
      display: flex;
      align-items: center;
      gap: 60px;
    }

    .hero-content {
      flex: 1;
    }

    .hero-content h1 {
      font-size: 48px;
      font-weight: 700;
      letter-spacing: -0.5px;
      color: var(--secondary-dark);
      line-height: 1.2;
      margin-bottom: 20px;
    }

    .hero-content p {
      font-size: 18px;
      color: var(--text-secondary);
      margin-bottom: 32px;
      line-height: 1.7;
    }

    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }

    .hero-image {
      flex: 1;
      position: relative;
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card-hover);
    }
    .hero-image img {
      width: 100%;
      height: auto;
      object-fit: cover;
      aspect-ratio: 4/3;
    }

    @media (max-width: 768px) {
      .hero {
        flex-direction: column;
        padding-top: calc(var(--nav-height) + 40px);
        gap: 40px;
      }
      .hero-content h1 {
        font-size: 32px;
      }
      .hero-image {
        order: -1;
      }
    }

    /* ----- 亮点网格 2x3 ----- */
    .highlights-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
      margin-top: 40px;
    }
    .highlight-item {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
      transition: 0.3s ease;
    }
    .highlight-item:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-card-hover);
    }
    .highlight-icon {
      font-size: 40px;
      margin-bottom: 16px;
    }
    .highlight-item h3 {
      font-size: 22px;
      font-weight: 600;
      margin-bottom: 10px;
    }
    @media (max-width: 1024px) {
      .highlights-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 520px) {
      .highlights-grid {
        grid-template-columns: 1fr;
      }
    }

    /* ----- 案例瀑布流(columns) ----- */
    .case-waterfall {
      columns: 3;
      column-gap: 24px;
      margin-top: 30px;
    }
    .case-card {
      break-inside: avoid;
      background: var(--card-bg);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      margin-bottom: 24px;
      transition: all 0.3s ease;
    }
    .case-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-card-hover);
    }
    .case-card img {
      border-radius: 16px 16px 0 0;
      width: 100%;
      display: block;
      transition: transform 0.3s;
    }
    .case-card:hover img {
      transform: scale(1.03);
    }
    .case-body {
      padding: 20px;
    }
    .case-tag {
      display: inline-block;
      background: rgba(10,224,240,0.12);
      color: #0B8A99;
      font-size: 13px;
      padding: 4px 12px;
      border-radius: 20px;
      margin-right: 6px;
    }
    @media (max-width: 1024px) {
      .case-waterfall { columns: 2; }
    }
    @media (max-width: 520px) {
      .case-waterfall { columns: 1; }
    }

    /* ----- 方案对比双卡 ----- */
    .compare-dual {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 30px;
    }
    .compare-card {
      background: var(--card-bg);
      border-radius: 20px;
      padding: 36px;
      box-shadow: var(--shadow-card);
    }
    .compare-card.traditional {
      border: 1px solid #E5E7EB;
      background: #F9FAFB;
    }
    .compare-card.kuaishou {
      border-top: 5px solid var(--primary);
    }
    @media (max-width: 768px) {
      .compare-dual { grid-template-columns: 1fr; }
    }

    /* ----- 数据滚动条 ----- */
    .stats-strip {
      background: #EDF2F7;
      padding: 48px 0;
      display: flex;
      justify-content: center;
      gap: 50px;
      flex-wrap: wrap;
      text-align: center;
    }
    .stat-item strong {
      font-size: 42px;
      color: var(--accent);
    }
    
    /* ----- FAQ 手风琴 ----- */
    .faq-item {
      margin-bottom: 14px;
      background: white;
      border-radius: 10px;
      box-shadow: 0 2px 8px rgba(0,0,0,0.04);
    }
    .faq-question {
      padding: 20px 24px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
      border-left: 4px solid var(--primary);
    }
    .faq-answer {
      padding: 0 24px 20px;
      display: none;
      background: #F0FAFF;
    }
    .faq-item.open .faq-answer {
      display: block;
    }

    /* CTA 横幅 */
    .cta-banner {
      background: var(--gradient-cta);
      border-radius: 24px;
      padding: 60px;
      text-align: center;
      color: white;
    }
    .btn-white {
      background: white;
      color: var(--accent);
      border-radius: 50px;
      padding: 14px 40px;
    }

    /* 页脚 */
    .footer {
      background: #0B1D3A;
      color: #CBD5E1;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 30px;
    }
    @media (max-width: 768px) {
      .footer-grid { grid-template-columns: 1fr; }
    }