/* roulang page: index */
:root {
      --primary: #E43D2A;
      --primary-dark: #C5301A;
      --secondary: #1A1A2E;
      --accent: #F5A623;
      --bg-light: #FAFAFA;
      --bg-gray: #F7F7F7;
      --text-main: #1A1A2E;
      --text-body: #4A4A4A;
      --text-muted: #888888;
      --white: #FFFFFF;
      --border-light: rgba(0, 0, 0, 0.06);
      --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.04);
      --shadow-card-hover: 0 8px 30px rgba(0, 0, 0, 0.08);
      --radius-card: 16px;
      --radius-btn: 8px;
      --radius-input: 8px;
      --font-sans: -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --font-number: 'Inter', var(--font-sans);
      --transition: 0.3s ease;
    }

    * {
      box-sizing: border-box;
    }

    body {
      margin: 0;
      font-family: var(--font-sans);
      line-height: 1.6;
      background-color: var(--bg-light);
      color: var(--text-body);
      -webkit-font-smoothing: antialiased;
    }

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

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

    button, input {
      font-family: inherit;
    }

    .container-custom {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 24px;
      padding-right: 24px;
    }

    @media (max-width: 480px) {
      .container-custom {
        padding-left: 16px;
        padding-right: 16px;
      }
    }

    /* 导航 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 50;
      transition: background var(--transition), box-shadow var(--transition);
      padding: 16px 0;
      background: transparent;
    }

    .navbar.scrolled {
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(12px);
      box-shadow: 0 1px 6px rgba(0, 0, 0, 0.08);
      padding: 12px 0;
    }

    .navbar .logo-text {
      font-weight: 700;
      font-size: 1.5rem;
      color: white;
      letter-spacing: -0.3px;
      transition: color var(--transition);
      display: flex;
      align-items: center;
      gap: 6px;
    }

    .navbar.scrolled .logo-text {
      color: var(--secondary);
    }

    .nav-link {
      color: white;
      font-weight: 500;
      font-size: 0.95rem;
      transition: color var(--transition);
      margin-left: 2rem;
      opacity: 0.9;
    }

    .navbar.scrolled .nav-link {
      color: var(--secondary);
    }

    .nav-link:hover {
      color: var(--accent);
      opacity: 1;
    }

    .btn-nav {
      background: var(--primary);
      color: white;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 0.9rem;
      transition: background var(--transition), transform var(--transition);
      margin-left: 2rem;
      white-space: nowrap;
    }

    .btn-nav:hover {
      background: var(--primary-dark);
      transform: scale(1.02);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
      padding: 4px;
    }

    .hamburger span {
      width: 24px;
      height: 2px;
      background: white;
      transition: var(--transition);
      display: block;
    }

    .navbar.scrolled .hamburger span {
      background: var(--secondary);
    }

    .mobile-menu {
      position: fixed;
      inset: 0;
      background: var(--secondary);
      flex-direction: column;
      justify-content: center;
      align-items: center;
      gap: 2.5rem;
      display: none;
      z-index: 40;
      opacity: 0;
      transition: opacity 0.4s;
    }

    .mobile-menu.active {
      display: flex;
      opacity: 1;
    }

    @media (max-width: 768px) {
      .desktop-nav {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .nav-link, .btn-nav {
        margin-left: 0;
      }
      .mobile-menu .nav-link {
        color: white;
        font-size: 1.5rem;
      }
      .mobile-menu .btn-nav {
        background: var(--accent);
        color: var(--secondary);
        font-size: 1.1rem;
        padding: 12px 32px;
      }
    }

    /* Hero */
    .hero-section {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: linear-gradient(135deg, #1A1A2E 0%, #16213E 100%);
      position: relative;
      overflow: hidden;
    }

    .hero-particles {
      position: absolute;
      inset: 0;
      background: radial-gradient(circle at 30% 40%, rgba(228,61,42,0.12) 0%, transparent 40%);
      pointer-events: none;
    }

    h1 {
      font-size: 3rem;
      font-weight: 700;
      line-height: 1.2;
      letter-spacing: -0.5px;
      color: white;
      position: relative;
      display: inline-block;
    }

    h1::after {
      content: '';
      position: absolute;
      bottom: -8px;
      left: 0;
      width: 70px;
      height: 4px;
      background: var(--accent);
      border-radius: 2px;
    }

    @media (max-width: 768px) {
      h1 {
        font-size: 2.2rem;
      }
      .hero-section {
        flex-direction: column;
        text-align: center;
        padding-top: 6rem;
        padding-bottom: 3rem;
      }
      h1::after {
        left: 50%;
        transform: translateX(-50%);
      }
    }

    /* 卡片 */
    .service-card {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 2rem;
      box-shadow: var(--shadow-card);
      transition: all var(--transition);
      border-left: 4px solid var(--primary);
      cursor: default;
    }

    .service-card:hover {
      box-shadow: var(--shadow-card-hover);
      transform: translateY(-4px);
    }

    /* 数字 */
    .stat-number {
      font-family: var(--font-number);
      font-size: 3rem;
      font-weight: 700;
      color: var(--primary);
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }

    .faq-question {
      cursor: pointer;
      padding: 1.25rem 0;
      font-weight: 600;
      color: var(--text-main);
      display: flex;
      justify-content: space-between;
      align-items: center;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease;
      color: #666;
    }

    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 1rem;
    }

    .faq-item.active .faq-question {
      color: var(--primary);
    }

    footer {
      background: #1A1A2E;
      color: #ccc;
    }