/* roulang page: index */
:root {
      --primary: #0F2B48;
      --primary-dark: #0B1E33;
      --accent: #0077ED;
      --accent-hover: #005fbe;
      --teal: #00A389;
      --surface-light: #F8FAFC;
      --surface-card: #FFFFFF;
      --surface-dark: #0B1523;
      --surface-dark-card: #152438;
      --text-main: #0F172A;
      --text-body: #334155;
      --text-muted: #64748B;
      --border-color: #E2E8F0;
      --radius: 12px;
      --radius-lg: 16px;
      --shadow-sm: 0 2px 8px rgba(15, 43, 72, 0.04);
      --shadow-md: 0 8px 24px -4px rgba(15, 43, 72, 0.08);
      --shadow-lg: 0 16px 36px -6px rgba(15, 43, 72, 0.12);
    }

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

    body {
      font-family: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
      color: var(--text-body);
      background-color: #ffffff;
      line-height: 1.75;
      overflow-x: hidden;
      scroll-behavior: smooth;
    }

    h1, h2, h3, h4, h5, h6 {
      color: var(--text-main);
      font-weight: 700;
      line-height: 1.35;
    }

    a {
      text-decoration: none;
      transition: all 0.25s ease;
    }

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

    /* 容器控制 */
    .app-container {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1rem;
      padding-right: 1rem;
    }
    @media (min-width: 640px) { .app-container { padding-left: 1.5rem; padding-right: 1.5rem; } }
    @media (min-width: 1024px) { .app-container { padding-left: 2rem; padding-right: 2rem; } }

    /* 板块通用间距与背景 */
    .app-section {
      padding-top: 5rem;
      padding-bottom: 5rem;
      position: relative;
    }
    @media (max-width: 768px) {
      .app-section {
        padding-top: 3.5rem;
        padding-bottom: 3.5rem;
      }
    }

    /* 按钮样式体系 */
    .btn-custom {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 0.85rem 1.85rem;
      border-radius: var(--radius);
      font-weight: 600;
      font-size: 0.95rem;
      transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
      cursor: pointer;
      gap: 0.5rem;
    }
    .btn-custom-primary {
      background-color: var(--accent);
      color: #ffffff;
      box-shadow: 0 4px 14px rgba(0, 119, 237, 0.35);
    }
    .btn-custom-primary:hover {
      background-color: var(--accent-hover);
      box-shadow: 0 6px 20px rgba(0, 119, 237, 0.45);
      transform: translateY(-2px);
      color: #ffffff;
    }
    .btn-custom-secondary {
      background-color: rgba(255, 255, 255, 0.12);
      color: #ffffff;
      border: 1px solid rgba(255, 255, 255, 0.25);
      backdrop-filter: blur(8px);
    }
    .btn-custom-secondary:hover {
      background-color: rgba(255, 255, 255, 0.22);
      border-color: rgba(255, 255, 255, 0.45);
      transform: translateY(-2px);
      color: #ffffff;
    }
    .btn-custom-outline {
      background-color: transparent;
      color: var(--primary);
      border: 1px solid var(--border-color);
    }
    .btn-custom-outline:hover {
      border-color: var(--accent);
      color: var(--accent);
      background-color: #F0F7FF;
      transform: translateY(-2px);
    }

    /* 卡片体系 */
    .app-card {
      background: var(--surface-card);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-lg);
      padding: 1.75rem;
      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
      box-shadow: var(--shadow-sm);
    }
    .app-card:hover {
      border-color: rgba(0, 119, 237, 0.4);
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }

    /* 移动端底部固定响应栏 */
    .mobile-sticky-action {
      display: none;
      position: fixed;
      bottom: 0;
      left: 0;
      right: 0;
      z-index: 999;
      background: rgba(15, 43, 72, 0.96);
      backdrop-filter: blur(12px);
      padding: 0.75rem 1rem;
      border-top: 1px solid rgba(255, 255, 255, 0.12);
    }
    @media (max-width: 768px) {
      .mobile-sticky-action {
        display: flex;
        gap: 0.75rem;
      }
      body {
        padding-bottom: 70px;
      }
    }