/* roulang page: index */
:root {
      --primary-deep: #0A0E27;
      --primary-accent: #E94057;
      --secondary-bg: #1B204A;
      --highlight-cyan: #00E5FF;
      --light-bg: #F5F6FA;
      --white: #FFFFFF;
      --text-light-muted: #B0B7D1;
      --text-dark-muted: #4A4F6A;
      --border-light: rgba(255,255,255,0.08);
      --border-card: rgba(255,255,255,0.12);
      --shadow-card-hover: 0 12px 32px rgba(0,229,255,0.12);
      --shadow-button-glow: 0 0 18px rgba(233,64,87,0.5);
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --transition: 0.25s ease;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
    }

    * {
      box-sizing: border-box;
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--primary-deep);
      color: var(--text-light-muted);
      margin: 0;
      line-height: 1.65;
      font-size: 16px;
      scroll-behavior: smooth;
      -webkit-font-smoothing: antialiased;
    }

    h1, h2, h3, h4, .h1, .h2, .h3 {
      font-weight: 700;
      letter-spacing: -0.02em;
    }

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

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

    .container-custom {
      max-width: 1200px;
      margin: 0 auto;
      padding-left: 20px;
      padding-right: 20px;
    }

    /* 导航 */
    .navbar-custom {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      backdrop-filter: blur(12px);
      background-color: rgba(10, 14, 39, 0.8);
      border-bottom: 1px solid rgba(255,255,255,0.06);
      padding: 16px 0;
      transition: var(--transition);
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }

    .logo-brand {
      font-size: 22px;
      font-weight: 800;
      color: var(--white);
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .logo-brand i {
      color: var(--highlight-cyan);
      font-size: 26px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 40px;
    }
    .nav-link-item {
      font-size: 15px;
      color: var(--text-light-muted);
      position: relative;
      padding-bottom: 6px;
      font-weight: 500;
      transition: color 0.2s;
    }
    .nav-link-item:hover {
      color: var(--white);
    }
    .nav-link-item.active {
      color: var(--white);
    }
    .nav-link-item.active::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 100%;
      height: 2px;
      background: var(--primary-accent);
      border-radius: 1px;
    }
    .nav-link-item.active::before {
      content: '';
      position: absolute;
      left: -12px;
      top: 50%;
      transform: translateY(-50%);
      width: 4px;
      height: 4px;
      background: var(--primary-accent);
      border-radius: 50%;
    }

    /* 移动端汉堡菜单 */
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 6px;
      background: transparent;
      border: none;
      cursor: pointer;
      padding: 8px;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--text-light-muted);
      border-radius: 2px;
      transition: 0.2s;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100vh;
      background: rgba(10,14,27,0.98);
      backdrop-filter: blur(20px);
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 32px;
      z-index: 999;
    }
    .mobile-menu a {
      font-size: 22px;
      color: var(--white);
      font-weight: 600;
    }

    /* Hero */
    .hero-section {
      padding: 160px 0 120px;
      background: radial-gradient(circle at 30% 40%, #1B204A 0%, #0A0E27 80%);
      position: relative;
      overflow: hidden;
    }
    .hero-bg-img {
      position: absolute;
      right: 0;
      top: 50%;
      transform: translateY(-50%);
      width: 48%;
      opacity: 0.75;
      border-radius: 24px;
      box-shadow: 0 0 40px rgba(0,229,255,0.15);
      border: 1px solid rgba(0,229,255,0.2);
    }
    .hero-title {
      font-size: 54px;
      font-weight: 800;
      color: var(--white);
      line-height: 1.2;
      max-width: 600px;
      margin-bottom: 24px;
    }
    .hero-highlight {
      color: var(--highlight-cyan);
    }
    .hero-sub {
      font-size: 18px;
      color: #8A90B4;
      max-width: 500px;
      margin-bottom: 36px;
    }
    .btn-primary-custom {
      background: var(--primary-accent);
      color: white;
      border: none;
      padding: 14px 34px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 16px;
      transition: 0.25s;
      display: inline-flex;
      align-items: center;
      gap: 8px;
      box-shadow: 0 4px 14px rgba(233,64,87,0.3);
    }
    .btn-primary-custom:hover {
      background: #c92e44;
      box-shadow: var(--shadow-button-glow);
      color: white;
    }
    .btn-outline-arrow {
      background: transparent;
      color: var(--white);
      border: none;
      padding: 12px 20px;
      font-weight: 500;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      transition: 0.2s;
    }
    .btn-outline-arrow i {
      transition: transform 0.2s;
    }
    .btn-outline-arrow:hover i {
      transform: translateX(6px);
    }

    /* 指标看板 */
    .metrics-section {
      background: linear-gradient(180deg, #0A0E27 0%, #141838 100%);
      padding: 80px 0;
    }
    .metric-card {
      background: rgba(255,255,255,0.03);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 28px 20px;
      text-align: center;
      backdrop-filter: blur(4px);
    }
    .metric-number {
      font-size: 42px;
      font-weight: 800;
      color: var(--white);
      font-feature-settings: "tnum";
    }
    .metric-unit {
      font-size: 18px;
      font-weight: 400;
      color: var(--highlight-cyan);
    }

    /* 服务卡片 */
    .services-section {
      background: var(--light-bg);
      padding: 100px 0;
      color: #0A0E27;
    }
    .service-card {
      background: var(--white);
      border-radius: var(--radius-md);
      padding: 32px 24px;
      border: 1px solid rgba(0,0,0,0.04);
      transition: all 0.3s ease;
      box-shadow: 0 2px 8px rgba(0,0,0,0.02);
    }
    .service-card:hover {
      transform: translateY(-6px);
      border-color: rgba(233,64,87,0.4);
      box-shadow: var(--shadow-card-hover);
    }
    .service-icon {
      font-size: 36px;
      color: var(--highlight-cyan);
      margin-bottom: 20px;
      transition: 0.2s;
    }
    .service-card:hover .service-icon {
      color: var(--primary-accent);
    }

    /* 对比区 */
    .compare-section {
      background: #0A0E27;
      padding: 100px 0;
    }
    .compare-col {
      background: rgba(255,255,255,0.02);
      border-radius: var(--radius-lg);
      padding: 36px 28px;
      border: 1px solid var(--border-light);
    }
    .compare-highlight {
      background: rgba(0,229,255,0.08);
      border-left: 4px solid var(--highlight-cyan);
    }

    /* FAQ */
    .faq-section {
      background: var(--light-bg);
      padding: 100px 0;
    }
    .accordion-button {
      background: white;
      font-weight: 600;
      font-size: 18px;
      color: #0A0E27;
      border-bottom: 1px solid #E8EAF0;
      padding: 20px 24px;
      box-shadow: none;
    }
    .accordion-button:not(.collapsed) {
      background-color: #F8F9FC;
      color: #0A0E27;
    }
    .accordion-body {
      background: #F8F9FC;
      padding: 20px 24px;
      line-height: 1.8;
      color: #2d3250;
    }

    /* CTA */
    .cta-section {
      background: radial-gradient(circle at 20% 30%, #1B204A, #0A0E27);
      padding: 100px 0;
    }
    .input-cta {
      background: rgba(255,255,255,0.06);
      border: 1px solid rgba(255,255,255,0.12);
      color: white;
      border-radius: var(--radius-sm);
      padding: 14px 20px;
    }
    .input-cta:focus {
      border-color: var(--highlight-cyan);
      box-shadow: 0 0 0 0.2rem rgba(0,229,255,0.2);
    }

    /* 页脚 */
    .footer-section {
      background: #0A0E27;
      padding: 60px 0 30px;
      border-top: 1px solid rgba(255,255,255,0.06);
    }
    .footer-link {
      color: #8A90B4;
      font-size: 14px;
      transition: 0.2s;
    }
    .footer-link:hover {
      color: var(--highlight-cyan);
    }
    .social-icon {
      width: 40px;
      height: 40px;
      border: 1px solid rgba(255,255,255,0.2);
      border-radius: 50%;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      color: #8A90B4;
      transition: 0.2s;
    }
    .social-icon:hover {
      border-color: var(--primary-accent);
      background: var(--primary-accent);
      color: white;
    }

    @media (max-width: 992px) {
      .hero-bg-img {
        position: relative;
        width: 100%;
        margin-top: 32px;
      }
      .hero-title {
        font-size: 40px;
      }
    }
    @media (max-width: 768px) {
      .nav-links {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .hero-title {
        font-size: 36px;
      }
      .metrics-section .row > div {
        margin-bottom: 20px;
      }
    }
    @media (max-width: 576px) {
      .hero-title {
        font-size: 32px;
      }
    }