/* roulang page: index */
:root {
      --primary: #0A66FF;
      --primary-glow: rgba(10,102,255,0.6);
      --secondary: #FFB800;
      --secondary-glow: rgba(255,184,0,0.7);
      --bg-deep: #0B0F19;
      --card-bg: rgba(255, 255, 255, 0.03);
      --card-border: rgba(255, 255, 255, 0.08);
      --text-primary: #FFFFFF;
      --text-secondary: #B0C4DE;
      --text-muted: #6B7B8D;
      --radius-lg: 16px;
      --radius-md: 8px;
      --shadow-card: 0 8px 32px rgba(0,0,0,0.4);
      --transition: 0.3s ease;
      --font-display: 'Inter', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
    }

    * {
      box-sizing: border-box;
    }

    body {
      margin: 0;
      background-color: var(--bg-deep);
      font-family: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
      color: var(--text-secondary);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
      display: flex;
      min-height: 100vh;
    }

    /* 左侧竖向导航 - 桌面端 */
    .side-nav {
      width: 240px;
      height: 100vh;
      position: fixed;
      left: 0;
      top: 0;
      background: var(--bg-deep);
      border-right: 1px solid rgba(255,255,255,0.06);
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      padding: 32px 24px;
      z-index: 30;
      transition: transform 0.3s ease;
    }

    .logo-area {
      display: flex;
      align-items: center;
      gap: 10px;
      margin-bottom: 48px;
    }

    .logo-icon {
      font-size: 32px;
      color: var(--primary);
      filter: drop-shadow(0 0 8px var(--primary-glow));
    }

    .logo-text {
      font-size: 22px;
      font-weight: 700;
      color: var(--text-primary);
      letter-spacing: 1px;
      font-family: var(--font-display);
    }

    .nav-links {
      display: flex;
      flex-direction: column;
      gap: 8px;
      flex: 1;
    }

    .nav-link {
      display: flex;
      align-items: center;
      gap: 12px;
      padding: 12px 16px;
      font-size: 16px;
      color: var(--text-secondary);
      text-decoration: none;
      border-radius: 8px;
      font-weight: 500;
      position: relative;
      transition: var(--transition);
    }

    .nav-link i {
      width: 20px;
      font-size: 18px;
      color: var(--text-muted);
      transition: var(--transition);
    }

    .nav-link:hover,
    .nav-link.active {
      color: var(--text-primary);
      background: rgba(10,102,255,0.08);
    }

    .nav-link:hover i,
    .nav-link.active i {
      color: var(--primary);
    }

    .nav-link::before {
      content: '';
      position: absolute;
      left: 0;
      top: 50%;
      transform: translateY(-50%);
      width: 3px;
      height: 0;
      background: var(--primary);
      border-radius: 0 4px 4px 0;
      transition: height 0.2s ease;
    }

    .nav-link:hover::before,
    .nav-link.active::before {
      height: 24px;
    }

    .bottom-info {
      font-size: 13px;
      color: var(--text-muted);
      border-top: 1px solid rgba(255,255,255,0.06);
      padding-top: 24px;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }

    .bottom-info i {
      margin-right: 6px;
      color: var(--secondary);
    }

    /* 主内容区 */
    .main-content {
      margin-left: 240px;
      width: calc(100% - 240px);
      background: var(--bg-deep);
      position: relative;
    }

    /* 移动端顶部导航 */
    .mobile-header {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 64px;
      background: rgba(11,15,25,0.9);
      backdrop-filter: blur(20px);
      border-bottom: 1px solid rgba(255,255,255,0.06);
      align-items: center;
      justify-content: space-between;
      padding: 0 20px;
      z-index: 40;
    }

    .hamburger {
      font-size: 24px;
      color: var(--text-primary);
      background: none;
      border: none;
      cursor: pointer;
    }

    .mobile-menu {
      display: none;
      position: fixed;
      top: 64px;
      left: 0;
      width: 100%;
      height: calc(100vh - 64px);
      background: var(--bg-deep);
      flex-direction: column;
      padding: 32px;
      gap: 16px;
      z-index: 45;
    }

    .mobile-menu a {
      font-size: 20px;
      color: var(--text-secondary);
      text-decoration: none;
      padding: 12px 0;
      border-bottom: 1px solid rgba(255,255,255,0.04);
      display: flex;
      align-items: center;
      gap: 12px;
    }

    /* 容器与板块 */
    .section {
      padding: 100px 0;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 32px;
    }

    h1, h2, h3 {
      font-family: var(--font-display);
      color: var(--text-primary);
    }

    h2 {
      font-size: 36px;
      font-weight: 600;
      margin-bottom: 20px;
      line-height: 1.3;
    }

    .section-title {
      text-align: center;
      margin-bottom: 56px;
    }

    .section-title p {
      color: var(--text-muted);
      max-width: 600px;
      margin: 0 auto;
    }

    /* Hero */
    .hero {
      display: flex;
      align-items: center;
      min-height: 90vh;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      position: relative;
    }

    .hero::before {
      content: '';
      position: absolute;
      inset: 0;
      background: radial-gradient(circle at 30% 40%, rgba(10,102,255,0.15), transparent 70%);
    }

    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
      position: relative;
      z-index: 2;
    }

    .hero-left {
      flex: 1;
    }

    .hero-right {
      flex: 1;
      display: flex;
      flex-wrap: wrap;
      gap: 20px;
      justify-content: center;
    }

    .hero h1 {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      margin-bottom: 20px;
      color: #fff;
    }

    .hero .sub {
      font-size: 18px;
      color: var(--text-secondary);
      margin-bottom: 32px;
    }

    .btn-group {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }

    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-md);
      font-weight: 600;
      text-decoration: none;
      box-shadow: 0 0 20px var(--primary-glow);
      transition: var(--transition);
      border: none;
      cursor: pointer;
      display: inline-block;
    }

    .btn-primary:hover {
      background: #1E8AFF;
      box-shadow: 0 0 35px var(--primary-glow);
      color: white;
    }

    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      padding: 14px 32px;
      border-radius: var(--radius-md);
      font-weight: 600;
      text-decoration: none;
      transition: var(--transition);
    }

    .btn-outline:hover {
      background: rgba(10,102,255,0.1);
      color: white;
    }

    .float-card {
      background: var(--card-bg);
      backdrop-filter: blur(20px);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-lg);
      padding: 24px;
      width: 140px;
      text-align: center;
      box-shadow: var(--shadow-card);
      color: white;
    }

    .float-card .big-num {
      font-size: 32px;
      font-weight: 700;
      color: var(--secondary);
      font-family: var(--font-display);
    }

    /* 数据看板 */
    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }

    .metric-card {
      background: var(--card-bg);
      backdrop-filter: blur(20px);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-lg);
      padding: 32px 24px;
      text-align: center;
      box-shadow: var(--shadow-card);
    }

    .metric-number {
      font-size: 56px;
      font-weight: 700;
      color: var(--secondary);
      font-family: var(--font-display);
      line-height: 1;
    }

    .metric-label {
      color: var(--text-secondary);
      margin-top: 12px;
      font-size: 16px;
    }

    /* 服务卡片网格 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .service-card {
      background: var(--card-bg);
      backdrop-filter: blur(20px);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-lg);
      padding: 32px;
      transition: var(--transition);
      box-shadow: var(--shadow-card);
    }

    .service-card:hover {
      border-color: rgba(255,255,255,0.2);
      transform: translateY(-4px);
      box-shadow: 0 16px 40px rgba(0,0,0,0.6);
    }

    .service-icon {
      font-size: 40px;
      color: var(--primary);
      margin-bottom: 20px;
    }

    .service-card h3 {
      font-size: 24px;
      margin-bottom: 12px;
    }

    .service-link {
      color: var(--secondary);
      text-decoration: none;
      font-weight: 500;
      margin-top: 16px;
      display: inline-block;
    }

    /* 对比区 */
    .comparison-row {
      display: flex;
      gap: 24px;
      align-items: stretch;
    }

    .compare-card {
      flex: 1;
      background: var(--card-bg);
      backdrop-filter: blur(20px);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-lg);
      padding: 40px;
    }

    .compare-card.highlight {
      border-color: var(--primary);
      box-shadow: 0 0 24px rgba(10,102,255,0.3);
    }

    .compare-value {
      font-size: 48px;
      font-weight: 700;
      color: var(--secondary);
      font-family: var(--font-display);
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }

    .faq-item {
      border-bottom: 1px solid rgba(255,255,255,0.06);
      padding: 20px 0;
      cursor: pointer;
    }

    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 20px;
      font-weight: 600;
      color: var(--text-primary);
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-secondary);
      padding-top: 0;
    }

    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-top: 16px;
    }

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

    .contact-form {
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 20px;
    }

    .contact-form input,
    .contact-form textarea {
      background: transparent;
      border: 1px solid rgba(255,255,255,0.2);
      border-radius: var(--radius-md);
      padding: 14px;
      color: white;
      outline: none;
    }

    .contact-form input:focus {
      border-color: var(--primary);
    }

    .btn-gold {
      background: var(--secondary);
      color: #0B0F19;
      font-weight: 700;
      padding: 16px;
      border: none;
      border-radius: var(--radius-md);
      cursor: pointer;
      box-shadow: 0 0 20px var(--secondary-glow);
      transition: var(--transition);
    }

    .info-card {
      background: var(--card-bg);
      backdrop-filter: blur(20px);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-lg);
      padding: 32px;
    }

    /* 页脚 */
    .footer {
      border-top: 1px solid rgba(255,255,255,0.06);
      padding: 48px 0;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }

    @media (max-width: 1024px) {
      .side-nav {
        display: none;
      }
      .main-content {
        margin-left: 0;
        width: 100%;
      }
      .mobile-header {
        display: flex;
      }
      .metrics-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .services-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }

    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
      }
      .metrics-grid,
      .services-grid {
        grid-template-columns: 1fr;
      }
      .comparison-row {
        flex-direction: column;
      }
      .contact-grid {
        flex-direction: column;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
      h2 {
        font-size: 28px;
      }
    }