/* roulang page: index */
/* 设计变量与全局重置 */
    :root {
      --deep-blue: #0A0F1E;
      --dark-bg: #10172A;
      --card-glass: rgba(30, 42, 68, 0.6);
      --card-border: rgba(255, 255, 255, 0.08);
      --accent-blue: #0D6EFD;
      --cyan-glow: #00F0FF;
      --purple-tag: #7B61FF;
      --warm-cta: #FFB800;
      --text-strong: #F0F4FF;
      --text-body: #B0C0E0;
      --text-muted: #6A7B9E;
      --radius-lg: 20px;
      --radius-md: 12px;
      --radius-sm: 8px;
      --shadow-card: 0 12px 32px rgba(0, 0, 0, 0.45);
      --shadow-glow: 0 0 20px rgba(13, 110, 253, 0.55);
    }
    * {
      box-sizing: border-box;
    }
    body {
      margin: 0;
      font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background: radial-gradient(ellipse at 30% 20%, #0A0F1E 0%, #10172A 100%);
      color: var(--text-body);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
      scroll-behavior: smooth;
    }
    /* 背景微噪点纹理 */
    body::before {
      content: "";
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background-image: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="100" height="100" viewBox="0 0 100 100"><filter id="noise"><feTurbulence type="fractalNoise" baseFrequency="0.8" numOctaves="2" stitchTiles="stitch"/></filter><rect width="100" height="100" filter="url(/%23noise)" opacity="0.04"/></svg>');
      pointer-events: none;
      z-index: 0;
    }
    .container-main {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
      position: relative;
      z-index: 2;
    }
    /* 玻璃拟态卡片基类 */
    .glass-card {
      background: var(--card-glass);
      backdrop-filter: blur(16px);
      -webkit-backdrop-filter: blur(16px);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-card);
    }
    .glass-card-hover:hover {
      border-color: rgba(0, 240, 255, 0.35);
      box-shadow: 0 16px 40px rgba(0, 240, 255, 0.15);
      transform: translateY(-4px);
      transition: all 0.3s ease;
    }
    .btn-primary-glow {
      background: var(--accent-blue);
      color: white;
      box-shadow: var(--shadow-glow);
      border-radius: var(--radius-sm);
      padding: 12px 28px;
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: all 0.25s ease;
      letter-spacing: 0.5px;
      border: none;
    }
    .btn-primary-glow:hover {
      background: #1a7bff;
      box-shadow: 0 0 28px rgba(13, 110, 253, 0.8);
      transform: translateY(-2px);
    }
    .btn-outline-cyan {
      background: transparent;
      border: 1px solid var(--cyan-glow);
      color: var(--cyan-glow);
      border-radius: var(--radius-sm);
      padding: 12px 28px;
      font-weight: 600;
      transition: all 0.25s ease;
    }
    .btn-outline-cyan:hover {
      background: rgba(0, 240, 255, 0.08);
      border-color: #33f5ff;
      box-shadow: 0 0 18px rgba(0, 240, 255, 0.4);
      transform: translateY(-2px);
    }
    /* 导航固定玻璃效果 */
    .nav-glass {
      background: rgba(10, 15, 30, 0.8);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-bottom: 1px solid rgba(255, 255, 255, 0.06);
    }
    /* 对比表高亮列 */
    .highlight-col {
      border-left: 2px solid var(--cyan-glow);
      border-right: 2px solid var(--cyan-glow);
      background: rgba(0, 240, 255, 0.04);
    }
    /* FAQ 手风琴动画 */
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1), padding 0.3s;
      background: rgba(13, 110, 253, 0.05);
      border-radius: 0 0 12px 12px;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding: 16px;
      border: 1px solid rgba(0, 240, 255, 0.2);
      box-shadow: inset 0 0 14px rgba(0, 240, 255, 0.1);
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
      color: var(--cyan-glow);
    }
    /* 案例卡片叠加层 */
    .case-overlay {
      background: linear-gradient(0deg, rgba(10,15,30,0.9) 10%, rgba(10,15,30,0.3) 70%);
    }
    .case-card:hover .case-overlay {
      background: linear-gradient(0deg, rgba(10,15,30,0.7) 10%, rgba(10,15,30,0.15) 70%);
    }
    /* 移动端汉堡菜单 */
    .mobile-menu {
      transition: opacity 0.3s ease, transform 0.3s ease;
      transform: translateY(-10px);
      opacity: 0;
      pointer-events: none;
    }
    .mobile-menu.open {
      transform: translateY(0);
      opacity: 1;
      pointer-events: auto;
    }
    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
      }
      .advantages-grid {
        grid-template-columns: repeat(1, 1fr);
      }
      .solutions-grid {
        grid-template-columns: 1fr;
      }
    }
    /* 图片占位背景 */
    .img-placeholder {
      background-color: #1E2A44;
      background-size: cover;
      background-position: center;
    }