/* roulang page: index */
:root {
      --primary: #1A5FDC;
      --primary-dark: #1246A8;
      --secondary: #00B4D8;
      --accent: #FF6B35;
      --accent-hover: #E55A2B;
      --bg-white: #FFFFFF;
      --bg-light: #F8FAFD;
      --text-dark: #0B1E3C;
      --text-body: #4A5568;
      --text-muted: #8899AA;
      --border-light: #E2E8F0;
      --success: #10B981;
      --danger: #EF4444;
      --radius-sm: 10px;
      --radius-md: 16px;
      --radius-lg: 24px;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-hover: 0 12px 32px rgba(26,95,220,0.12);
      --transition: 0.3s ease;
      --container-max: 1200px;
      --nav-height: 72px;
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    html {
      scroll-behavior: smooth;
    }
    body {
      font-family: -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background: var(--bg-white);
      color: var(--text-body);
      font-size: 16px;
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    button, input {
      font-family: inherit;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    .nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background: rgba(255,255,255,0.96);
      backdrop-filter: blur(8px);
      box-shadow: 0 1px 8px rgba(0,0,0,0.06);
      z-index: 1000;
      display: flex;
      align-items: center;
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 22px;
      color: var(--text-dark);
      letter-spacing: -0.3px;
    }
    .logo-icon {
      width: 36px;
      height: 36px;
      background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
      border-radius: 10px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 20px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      font-size: 16px;
      color: var(--text-body);
      font-weight: 500;
      position: relative;
      padding: 6px 0;
      transition: color 0.2s;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 50%;
      transform: translateX(-50%) scaleX(0);
      width: 100%;
      height: 2px;
      background: var(--primary);
      transition: transform 0.25s ease;
    }
    .nav-links a:hover {
      color: var(--primary);
    }
    .nav-links a:hover::after {
      transform: translateX(-50%) scaleX(1);
    }
    .btn-nav {
      background: var(--accent);
      color: white !important;
      padding: 10px 24px !important;
      border-radius: 30px;
      font-weight: 600;
      transition: background 0.2s;
    }
    .btn-nav:hover {
      background: var(--accent-hover);
    }
    .btn-nav::after {
      display: none;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
      padding: 8px;
    }
    .hamburger span {
      width: 26px;
      height: 2px;
      background: var(--text-dark);
      border-radius: 4px;
      transition: 0.3s;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: var(--nav-height);
      left: 0;
      width: 100%;
      background: white;
      box-shadow: 0 8px 24px rgba(0,0,0,0.1);
      padding: 24px;
      flex-direction: column;
      gap: 20px;
      z-index: 999;
      transform: translateY(-10px);
      opacity: 0;
      pointer-events: none;
      transition: 0.3s;
    }
    .mobile-menu.active {
      display: flex;
      transform: translateY(0);
      opacity: 1;
      pointer-events: auto;
    }
    /* 通用板块 */
    section {
      padding: 100px 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 64px;
    }
    .section-title h2 {
      font-size: clamp(32px, 5vw, 40px);
      font-weight: 700;
      color: var(--text-dark);
      margin-bottom: 12px;
      line-height: 1.3;
    }
    .section-title p {
      font-size: 18px;
      color: var(--text-muted);
      max-width: 600px;
      margin: 0 auto;
    }
    /* Hero */
    .hero {
      min-height: 90vh;
      display: flex;
      align-items: center;
      background: var(--bg-white);
      padding-top: var(--nav-height);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }
    .hero-content h1 {
      font-size: clamp(38px, 6vw, 52px);
      font-weight: 800;
      color: var(--text-dark);
      line-height: 1.2;
      margin-bottom: 20px;
    }
    .hero-content .highlight {
      color: var(--primary);
      position: relative;
    }
    .hero-content p {
      font-size: 18px;
      color: var(--text-body);
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 14px 32px;
      border-radius: 30px;
      font-weight: 600;
      font-size: 16px;
      transition: all 0.3s;
      cursor: pointer;
      border: none;
    }
    .btn-primary {
      background: var(--accent);
      color: white;
      box-shadow: 0 8px 20px rgba(255,107,53,0.25);
    }
    .btn-primary:hover {
      background: var(--accent-hover);
      transform: translateY(-2px);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
    }
    .hero-visual {
      position: relative;
    }
    .hero-img {
      width: 100%;
      border-radius: var(--radius-lg);
      box-shadow: 0 24px 48px rgba(26,95,220,0.15);
      transition: transform 0.4s;
      animation: float 6s ease-in-out infinite;
    }
    @keyframes float {
      0%, 100% { transform: translateY(0); }
      50% { transform: translateY(-10px); }
    }
    /* 指标看板 */
    #metrics {
      background: var(--bg-light);
    }
    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
      text-align: center;
    }
    .metric-item {
      background: white;
      padding: 40px 20px;
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }
    .metric-item:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }
    .metric-number {
      font-size: 48px;
      font-weight: 800;
      color: var(--primary);
      margin-bottom: 8px;
    }
    .metric-label {
      font-size: 16px;
      color: var(--text-muted);
      font-weight: 500;
    }
    /* 服务卡片 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }
    .service-card {
      background: white;
      padding: 40px 32px;
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
      text-align: center;
    }
    .service-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-6px);
    }
    .service-icon {
      width: 56px;
      height: 56px;
      background: rgba(0,180,216,0.1);
      border-radius: 16px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 20px;
      color: var(--secondary);
      font-size: 28px;
    }
    .service-card h3 {
      font-size: 22px;
      font-weight: 600;
      color: var(--text-dark);
      margin-bottom: 12px;
    }
    .service-card p {
      color: var(--text-body);
      font-size: 15px;
    }
    /* 对比 */
    .compare-wrapper {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
      align-items: start;
    }
    .compare-card {
      padding: 40px;
      border-radius: var(--radius-md);
      background: white;
      box-shadow: var(--shadow-sm);
    }
    .compare-card.bad {
      background: #F9FAFB;
      border: 1px solid var(--border-light);
    }
    .compare-card.good {
      background: white;
      border: 2px solid var(--primary);
      box-shadow: 0 12px 32px rgba(26,95,220,0.1);
    }
    .compare-card h3 {
      font-size: 24px;
      margin-bottom: 24px;
      color: var(--text-dark);
    }
    .compare-list {
      list-style: none;
    }
    .compare-list li {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-bottom: 16px;
      font-size: 16px;
    }
    .icon-check {
      color: var(--success);
      font-weight: bold;
    }
    .icon-cross {
      color: var(--danger);
      font-weight: bold;
    }
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 20px 0;
      cursor: pointer;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      font-size: 18px;
      color: var(--text-dark);
    }
    .faq-icon {
      font-size: 24px;
      color: var(--primary);
      transition: transform 0.3s;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-body);
      padding-top: 0;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-top: 12px;
    }
    .faq-item.open .faq-icon {
      transform: rotate(45deg);
    }
    /* CTA */
    .cta-section {
      background: linear-gradient(135deg, #1A5FDC 0%, #0077B6 100%);
      text-align: center;
      padding: 100px 0;
    }
    .cta-title {
      color: white;
      font-size: 36px;
      font-weight: 700;
      margin-bottom: 32px;
    }
    .cta-form {
      display: flex;
      gap: 12px;
      max-width: 480px;
      margin: 0 auto;
      flex-wrap: wrap;
      justify-content: center;
    }
    .cta-input {
      flex: 1;
      padding: 14px 20px;
      border-radius: 30px;
      border: none;
      font-size: 16px;
      outline: none;
      box-shadow: inset 0 2px 8px rgba(0,0,0,0.05);
    }
    .btn-cta {
      background: var(--accent);
      color: white;
      padding: 14px 32px;
      border-radius: 30px;
      font-weight: 700;
      border: none;
      cursor: pointer;
      transition: 0.2s;
    }
    .btn-cta:hover {
      background: var(--accent-hover);
    }
    .privacy-note {
      margin-top: 16px;
      color: rgba(255,255,255,0.7);
      font-size: 13px;
    }
    /* Footer */
    .footer {
      background: #0B1E3C;
      color: #CBD5E1;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer h4 {
      color: white;
      margin-bottom: 16px;
    }
    .footer a {
      color: #CBD5E1;
      font-size: 14px;
      display: block;
      margin-bottom: 8px;
    }
    .footer a:hover {
      color: white;
    }
    .copyright {
      margin-top: 40px;
      text-align: center;
      font-size: 14px;
      color: #8899AA;
      border-top: 1px solid rgba(255,255,255,0.1);
      padding-top: 24px;
    }
    /* 响应式 */
    @media (max-width: 1024px) {
      .hero-grid, .compare-wrapper {
        grid-template-columns: 1fr;
      }
      .services-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .metrics-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero-grid { text-align: center; }
      .hero-content p { margin: 0 auto 24px; }
      .hero-buttons { justify-content: center; }
      .services-grid, .metrics-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      section { padding: 60px 0; }
    }
    @media (max-width: 520px) {
      .footer-grid { grid-template-columns: 1fr; }
      .cta-form { flex-direction: column; }
    }