/* roulang page: index */
:root {
      --primary-deep: #0A1628;
      --accent-cyan: #00F0FF;
      --accent-red: #FF4655;
      --bg-light: #F4F6F9;
      --card-white: #FFFFFF;
      --text-main: #1A1A1A;
      --text-secondary: #5A6A7E;
      --text-muted: #8E9EAF;
      --border-light: #E2E8F0;
      --shadow-card: 0 4px 20px rgba(10, 22, 40, 0.06);
      --shadow-card-hover: 0 8px 30px rgba(10, 22, 40, 0.12);
      --radius-card: 12px;
      --radius-btn: 6px;
      --font-title: 'PingFang SC', 'Microsoft YaHei', sans-serif;
      --font-data: 'Inter', 'Roboto', sans-serif;
    }

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

    body {
      font-family: var(--font-title);
      background-color: var(--bg-light);
      color: var(--text-main);
      line-height: 1.6;
      padding-top: 0;
    }

    h1, h2, h3, h4, .title-font {
      font-family: var(--font-title);
      letter-spacing: -0.02em;
      font-weight: 600;
    }

    .data-number, .stat-value {
      font-family: var(--font-data);
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s;
    }

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

    button, .btn, input, textarea {
      font-family: inherit;
    }

    /* 覆盖 Bootstrap 默认 */
    .btn-primary {
      background-color: var(--accent-red) !important;
      border-color: var(--accent-red) !important;
      color: white !important;
      border-radius: var(--radius-btn) !important;
      font-weight: 600;
      transition: background 0.2s, border 0.2s;
    }
    .btn-primary:hover, .btn-primary:focus {
      background-color: #D93A46 !important;
      border-color: #D93A46 !important;
    }
    .btn-outline-info {
      border-color: var(--accent-cyan) !important;
      color: var(--accent-cyan) !important;
      border-radius: var(--radius-btn) !important;
      font-weight: 600;
    }
    .btn-outline-info:hover {
      background-color: rgba(0, 240, 255, 0.08) !important;
      color: var(--accent-cyan) !important;
    }

    .navbar-toggler:focus {
      box-shadow: 0 0 0 0.15rem var(--accent-cyan);
    }

    /* 导航 - 透明玻璃 */
    #mainNav {
      position: fixed;
      top: 0;
      width: 100%;
      z-index: 1030;
      background: rgba(10, 22, 40, 0.75);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(0, 240, 255, 0.15);
      box-shadow: 0 2px 20px rgba(0, 0, 0, 0.3);
      transition: background 0.3s ease, border 0.3s ease;
      padding: 0.5rem 0;
    }
    #mainNav.scrolled {
      background: #0A1628;
      border-bottom: 1px solid rgba(0, 240, 255, 0.25);
    }
    .navbar-brand {
      font-size: 1.4rem;
      font-weight: 700;
      color: var(--accent-cyan) !important;
      letter-spacing: 0.5px;
      position: relative;
    }
    .navbar-brand::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: -2px;
      width: 100%;
      height: 2px;
      background: var(--accent-cyan);
      opacity: 0.8;
    }
    .nav-link {
      color: rgba(255,255,255,0.85) !important;
      font-weight: 600;
      font-size: 0.9rem;
      margin: 0 0.2rem;
    }
    .nav-link:hover, .nav-link.active {
      color: var(--accent-cyan) !important;
    }
    .nav-cta-btn {
      background: var(--accent-red);
      border: none;
      color: white;
      font-weight: 600;
      padding: 0.5rem 1.2rem;
      border-radius: var(--radius-btn);
      height: 40px;
      line-height: 1.2;
      font-size: 0.9rem;
      transition: background 0.2s;
    }
    .nav-cta-btn:hover {
      background: #D93A46;
      color: white;
    }

    /* Hero */
    .hero-section {
      background: var(--primary-deep);
      min-height: 100vh;
      display: flex;
      align-items: center;
      position: relative;
      overflow: hidden;
      background-image: radial-gradient(circle at 20% 30%, rgba(0,240,255,0.08) 0%, transparent 40%);
    }
    .hero-content {
      position: relative;
      z-index: 2;
    }
    .hero-title {
      font-size: 2.8rem;
      font-weight: 700;
      color: white;
      line-height: 1.2;
    }
    .hero-sub {
      color: rgba(255,255,255,0.7);
      font-size: 1.1rem;
      max-width: 550px;
      margin-top: 1rem;
    }
    .hero-img {
      border-radius: 16px;
      border: 2px solid rgba(0,240,255,0.3);
      box-shadow: 0 20px 35px rgba(0,0,0,0.5);
    }
    .scroll-indicator {
      position: absolute;
      bottom: 25px;
      left: 50%;
      transform: translateX(-50%);
      color: var(--accent-cyan);
      font-size: 1.6rem;
      animation: bounce 2s infinite;
    }
    @keyframes bounce {
      0%,20%,50%,80%,100%{transform:translateX(-50%) translateY(0);}
      40%{transform:translateX(-50%) translateY(-8px);}
      60%{transform:translateX(-50%) translateY(-4px);}
    }

    /* 统计看板 */
    .stats-card {
      background: var(--card-white);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
    }
    .stat-item {
      text-align: center;
      padding: 1.5rem;
    }
    .stat-value {
      font-size: 2.4rem;
      font-weight: 700;
      color: var(--primary-deep);
      line-height: 1.2;
    }
    .stat-label {
      color: var(--text-secondary);
      font-size: 0.9rem;
      margin-top: 0.3rem;
    }

    /* 服务卡片 */
    .service-card {
      background: var(--card-white);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      border: 1px solid var(--border-light);
      padding: 1.8rem;
      transition: all 0.25s ease;
      height: 100%;
    }
    .service-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-card-hover);
      border-color: var(--accent-cyan);
    }
    .service-icon {
      color: var(--accent-cyan);
      font-size: 2.2rem;
    }

    /* 对比卡片 */
    .compare-card {
      background: var(--card-white);
      border-radius: var(--radius-card);
      padding: 1.8rem;
      border: 1px solid var(--border-light);
    }
    .before-card {
      border-left: 4px solid #A0AAB5;
    }
    .after-card {
      border-left: 4px solid var(--accent-cyan);
    }

    /* FAQ */
    .accordion-button:not(.collapsed) {
      background-color: #F8FAFC;
      color: var(--primary-deep);
      font-weight: 600;
      box-shadow: none;
      border-color: var(--border-light);
    }
    .accordion-button:focus {
      border-color: var(--accent-cyan);
      box-shadow: 0 0 0 0.15rem rgba(0,240,255,0.2);
    }
    .accordion-item {
      border: 1px solid var(--border-light);
      margin-bottom: 0.8rem;
      border-radius: 8px !important;
    }

    /* footer */
    footer {
      background: var(--primary-deep);
      color: rgba(255,255,255,0.7);
    }
    footer a {
      color: rgba(255,255,255,0.7);
    }
    footer a:hover {
      color: var(--accent-cyan);
    }

    @media (max-width: 768px) {
      .hero-title {
        font-size: 2rem;
      }
      .stat-value {
        font-size: 2rem;
      }
    }