/* roulang page: index */
:root {
      --primary-deep: #0A0E27;
      --accent-cyan: #00F0FF;
      --emphasis-red: #FF4D6D;
      --bg-dark: #060B1A;
      --card-bg: #0F1535;
      --text-white: #FFFFFF;
      --text-steel: #B0C4DE;
      --text-muted: #6C7A9C;
      --glass-bg: rgba(15, 21, 53, 0.6);
      --glass-border: rgba(0, 240, 255, 0.15);
      --blur-amount: 12px;
      --radius-card: 16px;
      --radius-btn: 50px;
      --radius-input: 12px;
      --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.4);
      --shadow-glow-cyan: 0 0 20px rgba(0, 240, 255, 0.5);
      --shadow-glow-red: 0 0 20px rgba(255, 77, 109, 0.5);
      --nav-width: 260px;
      --mobile-nav-height: 64px;
    }

    * {
      box-sizing: border-box;
    }

    body {
      font-family: 'Inter', 'PingFang SC', 'Microsoft YaHei', sans-serif;
      background-color: var(--bg-dark);
      color: var(--text-steel);
      margin: 0;
      line-height: 1.7;
      font-size: 1rem;
      overflow-x: hidden;
      -webkit-font-smoothing: antialiased;
    }

    h1, h2, h3, h4, h5, h6 {
      font-weight: 700;
      letter-spacing: -0.02em;
    }

    a {
      text-decoration: none;
      color: var(--accent-cyan);
      transition: all 0.3s ease;
    }

    a:hover {
      color: #33F5FF;
    }

    /* 自定义容器 */
    .custom-container {
      width: 100%;
      max-width: 1200px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }

    /* 左侧竖向导航 */
    .vertical-nav {
      position: fixed;
      top: 0;
      left: 0;
      width: var(--nav-width);
      height: 100vh;
      background: rgba(10, 14, 39, 0.85);
      backdrop-filter: blur(16px);
      -webkit-backdrop-filter: blur(16px);
      border-right: 1px solid var(--glass-border);
      display: flex;
      flex-direction: column;
      z-index: 1050;
      box-shadow: 4px 0 25px rgba(0,0,0,0.5);
      transition: transform 0.3s ease;
    }

    .logo-area {
      height: 80px;
      display: flex;
      align-items: center;
      padding-left: 1.8rem;
      border-bottom: 1px solid rgba(0, 240, 255, 0.25);
      margin-bottom: 1.5rem;
    }

    .logo-text {
      font-size: 1.8rem;
      font-weight: 800;
      color: var(--text-white);
      letter-spacing: 0.02em;
      background: linear-gradient(135deg, #FFFFFF 0%, #00F0FF 80%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }

    .nav-menu {
      flex: 1;
      display: flex;
      flex-direction: column;
      padding: 0 1rem;
      gap: 0.5rem;
    }

    .nav-link-item {
      display: flex;
      align-items: center;
      padding: 0.85rem 1.2rem;
      border-radius: 12px;
      color: var(--text-steel);
      font-weight: 500;
      font-size: 0.95rem;
      letter-spacing: 0.03em;
      position: relative;
      transition: all 0.25s ease;
      border-left: 4px solid transparent;
    }

    .nav-link-item i {
      width: 24px;
      margin-right: 12px;
      font-size: 1.1rem;
      color: var(--text-muted);
      transition: color 0.2s;
    }

    .nav-link-item:hover,
    .nav-link-item.active {
      color: var(--accent-cyan);
      background: rgba(0, 240, 255, 0.05);
      border-left: 4px solid var(--accent-cyan);
      box-shadow: 0 0 12px rgba(0,240,255,0.1);
    }

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

    /* 移动端顶部导航 */
    .mobile-nav {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--mobile-nav-height);
      background: rgba(6, 11, 26, 0.92);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-bottom: 1px solid var(--glass-border);
      z-index: 1040;
      align-items: center;
      justify-content: space-between;
      padding: 0 1.5rem;
    }

    .mobile-logo {
      font-size: 1.6rem;
      font-weight: 800;
      background: linear-gradient(135deg, #fff, #00F0FF);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    .hamburger {
      font-size: 1.8rem;
      color: var(--accent-cyan);
      background: none;
      border: none;
    }

    .mobile-menu-overlay {
      position: fixed;
      top: var(--mobile-nav-height);
      left: 0;
      width: 100%;
      height: calc(100vh - var(--mobile-nav-height));
      background: #060B1A;
      flex-direction: column;
      padding: 2rem;
      gap: 1rem;
      display: none;
      z-index: 1039;
    }

    .mobile-menu-overlay.show {
      display: flex;
    }

    .mobile-menu-overlay .nav-link-item {
      font-size: 1.2rem;
      padding: 1rem;
    }

    /* 主内容区域偏移 */
    .main-content {
      margin-left: var(--nav-width);
      width: calc(100% - var(--nav-width));
      transition: margin 0.3s;
    }

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

    @media (max-width: 992px) {
      .vertical-nav {
        display: none;
      }
      .mobile-nav {
        display: flex;
      }
      .main-content {
        margin-left: 0;
        width: 100%;
      }
      section {
        padding: 70px 0;
      }
    }

    /* 标题风格 */
    .section-title {
      font-size: 2.25rem;
      font-weight: 700;
      color: var(--accent-cyan);
      margin-bottom: 3rem;
      position: relative;
      display: inline-block;
    }
    .section-title::after {
      content: '';
      position: absolute;
      bottom: -10px;
      left: 0;
      width: 60px;
      height: 3px;
      background: var(--accent-cyan);
      box-shadow: 0 0 15px var(--accent-cyan);
    }

    /* 卡片玻璃拟态 */
    .glass-card {
      background: var(--glass-bg);
      backdrop-filter: blur(var(--blur-amount));
      -webkit-backdrop-filter: blur(var(--blur-amount));
      border: 1px solid var(--glass-border);
      border-radius: var(--radius-card);
      padding: 2rem;
      box-shadow: var(--shadow-card);
      transition: transform 0.3s ease, border-color 0.3s;
    }

    .glass-card:hover {
      transform: translateY(-6px);
      border-color: rgba(0,240,255,0.5);
      box-shadow: 0 12px 40px rgba(0,240,255,0.15);
    }

    /* 按钮 */
    .btn-primary-cyan {
      background: var(--accent-cyan);
      color: var(--primary-deep);
      border: none;
      border-radius: var(--radius-btn);
      padding: 0.75rem 2rem;
      font-weight: 600;
      letter-spacing: 0.05em;
      box-shadow: var(--shadow-glow-cyan);
      transition: all 0.3s;
    }
    .btn-primary-cyan:hover {
      background: #33F5FF;
      box-shadow: 0 0 30px rgba(0,240,255,0.8);
      color: #000;
    }

    .btn-outline-cyan {
      border: 1px solid var(--accent-cyan);
      color: var(--accent-cyan);
      background: transparent;
      border-radius: var(--radius-btn);
      padding: 0.75rem 2rem;
      font-weight: 600;
      transition: 0.3s;
    }
    .btn-outline-cyan:hover {
      background: rgba(0,240,255,0.1);
      color: #fff;
      border-color: #33F5FF;
    }

    .btn-danger-red {
      background: var(--emphasis-red);
      color: white;
      border: none;
      border-radius: var(--radius-btn);
      padding: 0.9rem 2.2rem;
      font-weight: 600;
      box-shadow: var(--shadow-glow-red);
      transition: 0.3s;
    }
    .btn-danger-red:hover {
      background: #FF6B85;
      box-shadow: 0 0 28px rgba(255,77,109,0.8);
    }

    /* 表单 */
    .form-control-dark {
      background: #0F1535;
      border: 1px solid rgba(0,240,255,0.2);
      border-radius: var(--radius-input);
      color: white;
      padding: 0.8rem 1.2rem;
    }
    .form-control-dark:focus {
      border-color: var(--accent-cyan);
      box-shadow: 0 0 12px rgba(0,240,255,0.5);
      background: #0F1535;
      color: white;
    }

    /* 数据数字 */
    .data-number {
      font-size: 2.5rem;
      font-weight: 800;
      color: var(--accent-cyan);
      font-feature-settings: "tnum";
      letter-spacing: -0.01em;
    }

    /* FAQ */
    .accordion-button-custom {
      background: #0F1535;
      color: white;
      border: none;
      box-shadow: none;
      font-weight: 600;
    }
    .accordion-button:not(.collapsed) {
      background: rgba(0,240,255,0.08);
      color: var(--accent-cyan);
      border-left: 4px solid var(--accent-cyan);
    }
    .accordion-item {
      background: transparent;
      border: 1px solid rgba(0,240,255,0.12);
      margin-bottom: 1rem;
      border-radius: 12px;
    }