/* roulang page: index */
:root {
      --primary: #E53935;
      --primary-dark: #c62828;
      --secondary: #1E88E5;
      --accent: #FFB300;
      --bg: #F5F6FA;
      --surface: #FFFFFF;
      --dark-bg: #1A1A2E;
      --text: #1F2329;
      --text-secondary: #86909C;
      --border: rgba(0,0,0,0.04);
      --success: #00B578;
      --warning: #FF9F0A;
      --error: #FA5151;
      --radius-sm: 8px;
      --radius: 12px;
      --radius-lg: 16px;
      --shadow-card: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-hover: 0 8px 24px rgba(0,0,0,0.08);
      --transition: 200ms ease;
      --container-max: 1200px;
      --header-height: 64px;
    }

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

    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      transition: all var(--transition);
      font-weight: 500;
    }

    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      right: 0;
      height: var(--header-height);
      background: rgba(255,255,255,0.9);
      backdrop-filter: blur(8px);
      box-shadow: 0 1px 4px rgba(0,0,0,0.04);
      z-index: 100;
      display: flex;
      align-items: center;
    }

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

    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: 1px;
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .logo span {
      color: var(--text);
      font-weight: 600;
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }
    .nav-menu a {
      font-size: 16px;
      color: var(--text);
      font-weight: 500;
      padding: 8px 0;
      position: relative;
      white-space: nowrap;
    }
    .nav-menu a:hover,
    .nav-menu a.active {
      color: var(--primary);
    }
    .nav-menu a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width var(--transition);
    }
    .nav-menu a:hover::after,
    .nav-menu a.active::after {
      width: 100%;
    }

    .btn-primary {
      background: var(--primary);
      color: white;
      border-radius: var(--radius-sm);
      padding: 10px 24px;
      font-weight: 600;
      box-shadow: 0 2px 8px rgba(229,57,53,0.2);
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      box-shadow: 0 4px 14px rgba(229,57,53,0.3);
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      border: 1px solid var(--border);
      color: var(--text);
      border-radius: var(--radius-sm);
      padding: 10px 24px;
      font-weight: 500;
    }
    .btn-outline:hover {
      border-color: var(--primary);
      color: var(--primary);
      background: rgba(229,57,53,0.03);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
      padding: 4px;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--text);
      border-radius: 2px;
      transition: var(--transition);
    }

    @media (max-width: 768px) {
      .nav-menu {
        position: fixed;
        top: var(--header-height);
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 24px;
        gap: 20px;
        box-shadow: 0 8px 20px rgba(0,0,0,0.06);
        transform: translateY(-120%);
        opacity: 0;
        transition: all 0.25s ease;
        pointer-events: none;
      }
      .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: auto;
      }
      .hamburger {
        display: flex;
      }
    }

    /* Hero */
    .hero {
      padding: calc(var(--header-height) + 48px) 0 60px;
      background: white;
      display: flex;
      align-items: center;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-content h1 {
      font-size: 44px;
      font-weight: 700;
      line-height: 1.3;
      color: var(--text);
      margin-bottom: 20px;
    }
    .hero-content p {
      font-size: 18px;
      color: var(--text-secondary);
      margin-bottom: 32px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image img {
      border-radius: var(--radius-lg);
      box-shadow: 0 20px 30px rgba(0,0,0,0.08);
      width: 100%;
      object-fit: cover;
    }

    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        text-align: center;
      }
      .hero-content h1 {
        font-size: 32px;
      }
      .hero-buttons {
        justify-content: center;
      }
      .hero-image {
        order: -1;
        max-width: 320px;
        margin: 0 auto;
      }
    }

    /* 通用区块 */
    section {
      padding: 80px 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 48px;
    }
    .section-title h2 {
      font-size: 32px;
      font-weight: 700;
      color: var(--text);
      margin-bottom: 12px;
    }
    .section-title p {
      color: var(--text-secondary);
      max-width: 600px;
      margin: 0 auto;
    }

    /* 核心优势 */
    .features {
      background: var(--bg);
    }
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .feature-card {
      background: var(--surface);
      border-radius: var(--radius);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
      transition: all var(--transition);
      text-align: center;
    }
    .feature-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }
    .feature-icon {
      font-size: 36px;
      color: var(--primary);
      margin-bottom: 20px;
    }
    .feature-card h3 {
      font-size: 20px;
      margin-bottom: 12px;
    }
    .feature-card p {
      color: var(--text-secondary);
      font-size: 15px;
    }

    /* 案例瀑布流 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .case-card {
      background: var(--surface);
      border-radius: var(--radius);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: all var(--transition);
    }
    .case-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-3px);
    }
    .case-img {
      height: 200px;
      background-size: cover;
      background-position: center;
    }
    .case-body {
      padding: 20px;
    }
    .case-body h3 {
      font-size: 18px;
      margin-bottom: 8px;
    }
    .case-stat {
      font-size: 28px;
      font-weight: 700;
      color: var(--accent);
    }

    /* 方案对比 */
    .compare-table {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
      align-items: start;
    }
    .plan-card {
      background: white;
      border-radius: var(--radius);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
      text-align: center;
    }
    .plan-card.featured {
      border: 2px solid var(--primary);
      box-shadow: 0 10px 25px rgba(229,57,53,0.1);
    }
    .plan-card h3 {
      font-size: 22px;
      margin-bottom: 12px;
    }
    .plan-list {
      list-style: none;
      text-align: left;
      margin: 24px 0;
    }
    .plan-list li {
      padding: 8px 0;
      font-size: 14px;
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      background: white;
      border-radius: var(--radius);
      margin-bottom: 12px;
      box-shadow: 0 1px 4px rgba(0,0,0,0.02);
    }
    .faq-question {
      width: 100%;
      padding: 20px;
      font-size: 16px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      padding: 0 20px 20px;
      color: var(--text-secondary);
      display: none;
      font-size: 15px;
    }
    .faq-item.open .faq-answer {
      display: block;
    }

    /* CTA 横幅 */
    .cta-banner {
      background: var(--dark-bg);
      color: white;
      text-align: center;
      padding: 80px 0;
    }
    .cta-banner h2 {
      font-size: 36px;
      margin-bottom: 16px;
    }
    .cta-banner .btn-primary {
      background: white;
      color: var(--primary);
      font-weight: 700;
    }

    /* Footer */
    .footer {
      background: #1F2329;
      color: #86909C;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer a:hover {
      color: white;
    }
    .copyright {
      border-top: 1px solid #2a2e35;
      margin-top: 40px;
      padding-top: 20px;
      font-size: 13px;
      text-align: center;
    }

    @media (max-width: 1024px) {
      .features-grid, .cases-grid, .compare-table {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 640px) {
      .features-grid, .cases-grid, .compare-table, .footer-grid {
        grid-template-columns: 1fr;
      }
      section {
        padding: 48px 0;
      }
    }