/* roulang page: index */
:root {
      --primary: #0A6EAA;
      --primary-dark: #0B4A6E;
      --accent: #F85C1E;
      --accent-hover: #E04A10;
      --bg: #F4F7FA;
      --white: #FFFFFF;
      --text: #1A2B3C;
      --text-secondary: #5A6B7C;
      --nav-bg: #0B1A2A;
      --border-light: #E0E8F0;
      --shadow-card: 0 4px 24px rgba(10,110,170,0.08);
      --shadow-hover: 0 8px 32px rgba(10,110,170,0.15);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-container: 16px;
      --spacing-section: 100px;
      --font-stack: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    }

    * {
      box-sizing: border-box;
    }

    body {
      font-family: var(--font-stack);
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.8;
      margin: 0;
      padding-top: 72px;
      overflow-x: hidden;
    }

    a {
      color: var(--primary);
      text-decoration: none;
      transition: color 0.25s ease, border-color 0.25s ease;
    }

    a:hover {
      color: var(--primary-dark);
    }

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

    h1, h2, h3, h4, .h1, .h2, .h3 {
      font-weight: 700;
      letter-spacing: 0.01em;
    }

    h1 {
      font-size: 3.2rem;
      line-height: 1.2;
      letter-spacing: 0.02em;
    }

    h2 {
      font-size: 2.4rem;
      margin-bottom: 1.5rem;
    }

    h3 {
      font-size: 1.4rem;
      font-weight: 600;
    }

    .section-spacing {
      padding: var(--spacing-section) 0;
    }

    @media (max-width: 768px) {
      h1 {
        font-size: 2.2rem;
      }
      h2 {
        font-size: 1.8rem;
      }
      .section-spacing {
        padding: 60px 0;
      }
      :root {
        --spacing-section: 60px;
      }
    }

    /* 导航栏自定义 */
    .navbar {
      background-color: var(--nav-bg) !important;
      height: 72px;
      box-shadow: 0 2px 10px rgba(0,0,0,0.2);
    }

    .navbar-brand {
      font-weight: 700;
      font-size: 1.6rem;
      color: white !important;
      letter-spacing: 2px;
      display: flex;
      align-items: center;
      gap: 10px;
    }

    .navbar-brand img {
      width: 36px;
      height: 36px;
      filter: drop-shadow(0 0 8px rgba(10,110,170,0.6));
    }

    .navbar-nav .nav-link {
      color: rgba(255,255,255,0.85) !important;
      font-weight: 500;
      padding: 0.75rem 1.2rem !important;
      position: relative;
      transition: 0.2s;
      margin: 0 2px;
    }

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

    .navbar-nav .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: 8px;
      left: 1.2rem;
      right: 1.2rem;
      height: 3px;
      background: var(--primary);
      box-shadow: 0 0 12px rgba(10,110,170,0.7);
      border-radius: 2px;
    }

    .btn-cta-nav {
      background: var(--accent);
      color: white !important;
      border-radius: var(--radius-btn);
      padding: 0.5rem 1.8rem !important;
      font-weight: 600;
      transition: 0.2s;
      border: none;
      margin-left: 8px;
    }

    .btn-cta-nav:hover {
      background: var(--accent-hover);
      color: white;
    }

    .offcanvas {
      background-color: var(--nav-bg);
    }
    .offcanvas .nav-link {
      color: white !important;
    }
    .offcanvas .nav-link.active {
      color: var(--primary) !important;
    }

    /* Hero */
    #hero {
      background: linear-gradient(135deg, rgba(11,26,42,0.8) 0%, rgba(10,110,170,0.5) 100%), url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      min-height: 100vh;
      display: flex;
      align-items: center;
      color: white;
      position: relative;
    }

    .hero-title {
      color: white;
    }

    .btn-hero-primary {
      background: var(--accent);
      border: none;
      padding: 16px 40px;
      font-weight: 700;
      font-size: 1.2rem;
      border-radius: var(--radius-btn);
      color: white;
      transition: all 0.3s;
      display: inline-flex;
      align-items: center;
      gap: 10px;
    }

    .btn-hero-primary:hover {
      background: var(--accent-hover);
      box-shadow: 0 0 20px rgba(248,92,30,0.7);
      transform: translateY(-2px);
      color: white;
    }

    .hero-sub-link {
      color: rgba(255,255,255,0.8);
      border-bottom: 1px dashed rgba(255,255,255,0.5);
      font-weight: 500;
    }

    /* 卡片与区块 */
    .card-custom {
      background: var(--white);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      padding: 32px;
      transition: all 0.3s ease;
      border: none;
      height: 100%;
    }

    .card-custom:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }

    .text-accent {
      color: var(--accent);
    }

    .bg-primary-gradient {
      background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    }

    .btn-outline-white {
      border: 1px solid white;
      color: white;
      background: transparent;
      border-radius: var(--radius-btn);
      padding: 12px 28px;
      font-weight: 600;
      transition: 0.3s;
    }
    .btn-outline-white:hover {
      background: white;
      color: var(--primary);
    }

    .stat-number {
      font-size: 3.5rem;
      font-weight: 800;
      color: var(--accent);
      line-height: 1.1;
    }

    .accordion-button:not(.collapsed) {
      background-color: #F8FAFD;
      color: var(--primary);
      box-shadow: none;
    }
    .accordion-button:focus {
      box-shadow: none;
      border-color: var(--primary);
    }
    .accordion-item {
      border: 1px solid var(--border-light);
      border-radius: var(--radius-btn) !important;
      margin-bottom: 12px;
    }

    footer {
      background: var(--nav-bg);
      color: rgba(255,255,255,0.7);
    }
    footer h5 {
      color: white;
      font-weight: 600;
    }
    footer a {
      color: rgba(255,255,255,0.6);
    }
    footer a:hover {
      color: var(--primary);
    }

    @media (max-width: 768px) {
      .navbar-collapse {
        background: var(--nav-bg);
        padding: 20px;
        border-radius: 0 0 12px 12px;
      }
      .stat-number {
        font-size: 2.8rem;
      }
    }