/* roulang page: index */
/* 品牌设计变量与全局样式 */
    :root {
      --primary-1: #0D7377;
      --primary-2: #14A3A8;
      --primary-gradient: linear-gradient(135deg, #0D7377 0%, #14A3A8 100%);
      --accent-gold: #F5A623;
      --text-slate: #5C6B7A;
      --text-dark: #1e2b3c;
      --bg-light: #F4F8FA;
      --bg-white: #FFFFFF;
      --coral-red: #FF6B6B;
      --border-light: rgba(13, 115, 119, 0.12);
      --shadow-card: 0 10px 25px -8px rgba(0,0,0,0.04), 0 4px 10px -4px rgba(0,0,0,0.02);
      --shadow-hover: 0 18px 35px -10px rgba(0,0,0,0.08), 0 8px 15px -6px rgba(0,0,0,0.04);
      --radius-xl: 24px;
      --radius-lg: 20px;
      --radius-md: 16px;
      --radius-btn: 12px;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', system-ui, -apple-system, 'Inter', sans-serif;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-light);
      color: var(--text-slate);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      display: flex;
      flex-direction: column;
    }

    /* 桌面端左侧竖向导航布局 */
    .app-layout {
      display: flex;
      min-height: 100vh;
    }

    /* 左侧导航 (桌面) */
    .side-nav {
      width: 250px;
      background: rgba(13, 115, 119, 0.95);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      background: linear-gradient(180deg, #0A4A4D 0%, #0D7377 100%);
      color: white;
      display: flex;
      flex-direction: column;
      padding: 2rem 0 1.5rem;
      position: fixed;
      top: 0;
      left: 0;
      height: 100vh;
      z-index: 40;
      box-shadow: 4px 0 25px rgba(0,0,0,0.15);
      transition: transform 0.3s ease;
    }

    .brand-area {
      padding: 0 1.5rem 1.5rem;
      border-bottom: 2px solid rgba(245, 166, 35, 0.5);
      margin-bottom: 2rem;
      text-align: center;
    }

    .brand-logo {
      font-size: 1.7rem;
      font-weight: 800;
      letter-spacing: 1px;
      color: white;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
    }
    .brand-logo i {
      color: var(--accent-gold);
      font-size: 2rem;
    }

    .nav-links {
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 0.3rem;
      padding: 0 0.8rem;
    }

    .nav-item {
      color: rgba(255,255,255,0.8);
      padding: 0.85rem 1.2rem;
      border-radius: 12px;
      font-weight: 500;
      transition: all 0.25s ease;
      display: flex;
      align-items: center;
      gap: 10px;
      border-left: 4px solid transparent;
      text-decoration: none;
      font-size: 1rem;
    }

    .nav-item i {
      width: 20px;
      font-size: 1.1rem;
    }

    .nav-item:hover {
      background: rgba(255,255,255,0.1);
      color: white;
      border-left: 4px solid var(--accent-gold);
      transform: translateX(4px);
    }

    .nav-bottom {
      padding: 1.5rem 1.5rem 0;
      font-size: 0.85rem;
      color: rgba(255,255,255,0.65);
      border-top: 1px solid rgba(255,255,255,0.15);
      margin-top: 1rem;
    }

    /* 主内容区域 */
    .main-content {
      margin-left: 250px;
      flex: 1;
      width: calc(100% - 250px);
      background: var(--bg-light);
    }

    /* 移动端顶部导航 */
    .mobile-nav {
      display: none;
      background: white;
      padding: 0.9rem 1.5rem;
      align-items: center;
      justify-content: space-between;
      box-shadow: 0 4px 15px rgba(0,0,0,0.04);
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255,255,255,0.9);
      backdrop-filter: blur(8px);
    }

    .mobile-brand {
      font-weight: 800;
      font-size: 1.4rem;
      color: var(--primary-1);
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .mobile-brand i { color: var(--accent-gold); }

    .hamburger {
      font-size: 1.8rem;
      color: var(--primary-1);
      cursor: pointer;
    }

    .mobile-menu {
      display: none;
      flex-direction: column;
      background: white;
      position: absolute;
      top: 100%;
      left: 0;
      width: 100%;
      box-shadow: 0 15px 25px rgba(0,0,0,0.08);
      padding: 1rem;
      border-top: 1px solid #eee;
    }
    .mobile-menu a {
      padding: 0.9rem 1rem;
      color: var(--text-dark);
      font-weight: 500;
      text-decoration: none;
      border-radius: 10px;
    }
    .mobile-menu a:hover {
      background: #f0f7f8;
      color: var(--primary-1);
    }

    /* 通用区块 */
    .section {
      padding: 5rem 2.5rem;
      max-width: 1300px;
      margin: 0 auto;
    }

    h2 {
      font-size: 2.4rem;
      font-weight: 700;
      color: var(--text-dark);
      margin-bottom: 1rem;
      position: relative;
      display: inline-block;
    }
    h2::after {
      content: '';
      display: block;
      width: 55px;
      height: 5px;
      background: var(--primary-gradient);
      border-radius: 4px;
      margin-top: 0.5rem;
    }

    .btn-primary {
      background: var(--primary-gradient);
      color: white;
      font-weight: 600;
      padding: 0.9rem 2.2rem;
      border-radius: var(--radius-btn);
      transition: all 0.3s;
      box-shadow: 0 6px 18px rgba(13,115,119,0.3);
      display: inline-block;
      text-align: center;
      border: none;
      cursor: pointer;
    }
    .btn-primary:hover {
      transform: scale(1.03);
      box-shadow: 0 10px 22px rgba(13,115,119,0.4);
    }
    .btn-outline {
      border: 2px solid var(--primary-1);
      color: var(--primary-1);
      background: transparent;
      font-weight: 600;
      padding: 0.85rem 2rem;
      border-radius: var(--radius-btn);
      transition: 0.3s;
    }
    .btn-outline:hover {
      background: rgba(13,115,119,0.08);
    }

    .card {
      background: white;
      border-radius: var(--radius-lg);
      padding: 2rem 1.8rem;
      box-shadow: var(--shadow-card);
      transition: all 0.25s;
      border: 1px solid var(--border-light);
      height: 100%;
    }
    .card:hover {
      transform: translateY(-8px);
      box-shadow: var(--shadow-hover);
      border-color: var(--primary-2);
    }

    /* 响应式 */
    @media (max-width: 1024px) {
      .side-nav {
        display: none;
      }
      .main-content {
        margin-left: 0;
        width: 100%;
      }
      .mobile-nav {
        display: flex;
      }
      .section {
        padding: 3.5rem 1.5rem;
      }
    }
    @media (max-width: 768px) {
      h2 { font-size: 1.8rem; }
    }