/* roulang page: index */
:root {
      --primary: #E63946;
      --primary-dark: #C1121F;
      --secondary-dark: #1D1D1F;
      --accent: #00B4D8;
      --bg-warm: #F8F7F4;
      --white: #FFFFFF;
      --text-main: #1D1D1F;
      --text-secondary: #6B7280;
      --text-light: #9CA3AF;
      --border-light: #E5E7EB;
      --shadow-sm: 0 2px 8px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.10);
      --shadow-lg: 0 16px 40px rgba(0,0,0,0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-tag: 6px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", system-ui, -apple-system, sans-serif;
      --font-mono: "SF Mono", "Menlo", "Courier New", monospace;
      --max-width: 1280px;
      --header-height: 72px;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-warm);
      color: var(--text-main);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }

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

    a {
      text-decoration: none;
      color: inherit;
    }

    button, input, textarea {
      font-family: inherit;
    }

    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 40px;
    }

    /* 导航样式 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--header-height);
      z-index: 1000;
      display: flex;
      align-items: center;
      transition: background 0.3s ease, box-shadow 0.3s ease;
      background: transparent;
    }

    .header.scrolled {
      background: var(--white);
      box-shadow: 0 1px 6px rgba(0,0,0,0.08);
    }

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

    .logo {
      display: flex;
      align-items: center;
      font-weight: 700;
      font-size: 24px;
      color: var(--white);
      transition: color 0.3s;
      letter-spacing: -0.5px;
    }

    .header.scrolled .logo {
      color: var(--secondary-dark);
    }

    .logo-icon {
      margin-right: 10px;
      font-size: 28px;
      color: var(--primary);
    }

    .nav-links {
      display: flex;
      gap: 36px;
      align-items: center;
    }

    .nav-links a {
      font-size: 15px;
      font-weight: 500;
      color: rgba(255,255,255,0.9);
      transition: color 0.2s, border-bottom 0.2s;
      position: relative;
      padding-bottom: 4px;
    }

    .header.scrolled .nav-links a {
      color: var(--text-main);
    }

    .nav-links a:hover,
    .nav-links a.active {
      color: var(--white);
    }

    .header.scrolled .nav-links a:hover,
    .header.scrolled .nav-links a.active {
      color: var(--primary);
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 3px;
      background: var(--primary);
      transition: width 0.2s;
    }

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

    .nav-cta {
      background: var(--primary);
      color: white;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 14px;
      transition: background 0.2s, box-shadow 0.2s;
      margin-left: 20px;
    }

    .nav-cta:hover {
      background: var(--primary-dark);
      box-shadow: 0 0 0 2px rgba(230,57,70,0.3);
    }

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

    .hamburger span {
      width: 24px;
      height: 2px;
      background: white;
      transition: 0.3s;
    }

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

    /* 移动端菜单 */
    .mobile-menu {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100vh;
      background: var(--secondary-dark);
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 32px;
      transform: translateY(-100%);
      transition: transform 0.4s ease;
      z-index: 999;
    }

    .mobile-menu.open {
      transform: translateY(0);
    }

    .mobile-menu a {
      color: white;
      font-size: 24px;
      font-weight: 600;
    }
    .mobile-menu .nav-cta {
      margin-left: 0;
      font-size: 18px;
      padding: 14px 32px;
    }

    /* Hero */
    #hero {
      background: linear-gradient(135deg, #1D1D1F 0%, #2B2B2F 100%);
      min-height: 100vh;
      display: flex;
      align-items: center;
      padding-top: var(--header-height);
      position: relative;
      overflow: hidden;
      color: white;
    }

    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
      width: 100%;
    }

    .hero-left {
      flex: 1;
    }

    .hero-right {
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 24px;
    }

    .hero h1 {
      font-size: 48px;
      font-weight: 800;
      line-height: 1.2;
      letter-spacing: -0.02em;
      margin-bottom: 20px;
    }

    .hero-sub {
      font-size: 18px;
      color: #D1D5DB;
      margin-bottom: 36px;
      max-width: 480px;
    }

    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      display: inline-block;
      transition: 0.2s;
      border: none;
      cursor: pointer;
    }

    .btn-primary:hover {
      background: var(--primary-dark);
      box-shadow: 0 0 0 4px rgba(230,57,70,0.25);
    }

    .btn-outline {
      background: transparent;
      border: 2px solid var(--accent);
      color: var(--accent);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: 0.2s;
      display: inline-block;
    }

    .btn-outline:hover {
      background: var(--accent);
      color: white;
    }

    .data-card {
      background: rgba(255,255,255,0.08);
      backdrop-filter: blur(12px);
      border-radius: var(--radius-card);
      padding: 28px;
      color: white;
      border: 1px solid rgba(255,255,255,0.1);
    }

    .big-number {
      font-family: var(--font-mono);
      font-size: 40px;
      font-weight: 700;
      color: var(--accent);
      text-shadow: 0 0 10px rgba(0,180,216,0.4);
    }

    /* 板块通用 */
    section {
      padding: 100px 0;
    }

    .section-title {
      font-size: 36px;
      font-weight: 700;
      margin-bottom: 20px;
      color: var(--secondary-dark);
    }

    /* Metrics */
    #metrics {
      background: var(--bg-warm);
    }

    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 24px;
      margin-top: 40px;
    }

    .metric-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 28px;
      box-shadow: var(--shadow-sm);
      transition: 0.2s;
    }

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

    .metric-value {
      font-family: var(--font-mono);
      font-size: 34px;
      font-weight: 700;
      color: var(--primary);
    }

    /* Services 非对称网格 */
    .services-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr;
      gap: 24px;
      margin-top: 40px;
    }

    .service-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-sm);
      transition: 0.2s;
      border-left: 3px solid transparent;
    }

    .service-card:hover {
      border-left: 3px solid var(--accent);
      box-shadow: var(--shadow-md);
    }

    .tag {
      background: transparent;
      border: 1px solid var(--primary);
      color: var(--primary);
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 12px;
      font-weight: 600;
    }

    /* Compare */
    .compare-container {
      display: flex;
      align-items: center;
      gap: 24px;
      margin-top: 40px;
    }

    .compare-box {
      flex: 1;
      background: white;
      padding: 36px;
      border-radius: var(--radius-card);
    }

    .vs-badge {
      width: 48px;
      height: 48px;
      background: var(--primary);
      color: white;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 800;
    }

    /* FAQ */
    .faq-item {
      background: white;
      border-radius: var(--radius-card);
      margin-bottom: 16px;
      box-shadow: var(--shadow-sm);
    }

    .faq-question {
      padding: 24px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      border-left: 4px solid var(--accent);
    }

    /* 表单 */
    .contact-grid {
      display: flex;
      gap: 40px;
      margin-top: 40px;
    }

    .form-input {
      width: 100%;
      padding: 14px;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-btn);
      margin-bottom: 20px;
    }

    .form-input:focus {
      border-color: var(--primary);
      outline: none;
    }

    .footer {
      background: var(--secondary-dark);
      color: #E5E7EB;
      padding: 60px 0 30px;
    }

    @media (max-width: 1024px) {
      .container { padding: 0 24px; }
      .metrics-grid { grid-template-columns: repeat(2,1fr); }
      .services-grid { grid-template-columns: 1fr 1fr; }
      .hero-grid { flex-direction: column; }
    }

    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero h1 { font-size: 36px; }
      .compare-container { flex-direction: column; }
      .contact-grid { flex-direction: column; }
    }

    @media (max-width: 480px) {
      .metrics-grid { grid-template-columns: 1fr; }
      .services-grid { grid-template-columns: 1fr; }
      .hero h1 { font-size: 28px; }
    }