/* roulang page: index */
/* ----- 设计变量 / RESET ----- */
    :root {
      --primary: #0B3D2E;
      --primary-light: #1a5a45;
      --accent: #F5A623;
      --accent-hover: #E09515;
      --dark: #1A1A1A;
      --text: #333333;
      --text-muted: #5a6a65;
      --bg: #F4F7F6;
      --white: #FFFFFF;
      --border-light: #E8EDEB;
      --radius-sm: 8px;
      --radius: 12px;
      --radius-lg: 16px;
      --shadow-card: 0 4px 20px rgba(0,0,0,0.06);
      --shadow-hover: 0 12px 28px rgba(0,0,0,0.12);
      --transition: 0.25s ease;
      --container: 1240px;
      --nav-height: 72px;
    }
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; }
    body {
      font-family: 'Inter', 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      font-size: 16px;
      line-height: 1.7;
      color: var(--text);
      background: var(--bg);
      -webkit-font-smoothing: antialiased;
    }
    .container { max-width: var(--container); margin: 0 auto; padding: 0 24px; }
    @media (max-width: 768px) { .container { padding: 0 16px; } }

    h1, h2, h3 { font-weight: 700; color: var(--dark); line-height: 1.3; }
    h1 { font-size: clamp(40px, 6vw, 56px); }
    h2 { font-size: clamp(30px, 5vw, 40px); margin-bottom: 1rem; }
    h3 { font-size: clamp(20px, 3.5vw, 26px); }
    p { color: var(--text-muted); line-height: 1.8; max-width: 65ch; }
    a { text-decoration: none; color: inherit; }

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

    button, .btn { cursor: pointer; border: none; font-weight: 700; display: inline-flex; align-items: center; justify-content: center; gap: 6px; transition: var(--transition); white-space: nowrap; }

    .sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); border: 0; }

    /* ----- 组件：按钮 ----- */
    .btn-primary {
      background: var(--accent); color: var(--primary); border-radius: var(--radius-sm);
      padding: 0.8rem 2rem; font-size: 1rem;
    }
    .btn-primary:hover { background: var(--accent-hover); transform: scale(1.03); box-shadow: 0 8px 18px rgba(245,166,35,0.3); }
    .btn-outline {
      background: transparent; border: 2px solid var(--primary); color: var(--primary);
      border-radius: var(--radius-sm); padding: 0.8rem 2rem; font-size: 1rem;
    }
    .btn-outline:hover { background: var(--primary); color: white; }

    /* 版块内间距 */
    section { padding: 5rem 0; }
    @media (max-width: 768px) { section { padding: 3.5rem 0; } }

    .section-title {
      display: flex; flex-direction: column; margin-bottom: 2.5rem;
    }
    .section-title h2 { position: relative; display: inline-block; }
    .section-title h2::after {
      content: ''; display: block; width: 50px; height: 4px; background: var(--accent);
      margin-top: 0.6rem; border-radius: 2px;
    }
    .text-center h2::after { margin-left: auto; margin-right: auto; }

    /* 非对称网格亮点 */
    .feature-grid {
      display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px;
    }

    /* ----- NAV ----- */
    .navbar {
      position: sticky; top: 0; z-index: 100; background: rgba(255,255,255,0.96);
      backdrop-filter: blur(12px); height: var(--nav-height); border-bottom: 1px solid var(--border-light);
      display: flex; align-items: center; justify-content: center;
    }
    .nav-container {
      display: flex; justify-content: space-between; align-items: center; width: 100%;
      max-width: var(--container); padding: 0 24px;
    }
    .logo { display: flex; align-items: center; gap: 8px; font-weight: 800; font-size: 1.5rem; color: var(--primary); }
    .logo i { font-size: 2rem; color: var(--accent); }
    .nav-links { display: flex; gap: 2.2rem; align-items: center; }
    .nav-links a { font-weight: 600; font-size: 0.95rem; color: var(--text); position: relative; padding: 0.25rem 0; }
    .nav-links a.active-link::after {
      content: ''; position: absolute; bottom: -6px; left: 0; width: 100%; height: 3px;
      background: var(--primary); border-radius: 3px;
    }
    .nav-links a:hover { color: var(--accent); }
    .btn-nav { background: var(--accent); color: var(--primary); padding: 0.55rem 1.4rem; border-radius: 30px; font-weight: 700; font-size: 0.9rem; margin-left: 0.6rem; }
    .btn-nav:hover { background: var(--accent-hover); }

    .hamburger { display: none; flex-direction: column; gap: 5px; background: none; border: none; }
    .hamburger span { width: 24px; height: 3px; background: var(--primary); border-radius: 2px; transition: 0.2s; }

    @media (max-width: 1024px) {
      .hamburger { display: flex; }
      .nav-links { position: fixed; top: 0; right: 0; width: 70%; max-width: 320px; height: 100vh; background: white; flex-direction: column; padding: 6rem 2rem; gap: 2rem; transform: translateX(100%); transition: 0.3s; box-shadow: -5px 0 25px rgba(0,0,0,0.1); }
      .nav-links.open { transform: translateX(0); }
    }

    /* HERO 双栏 */
    .hero .grid { display: grid; grid-template-columns: 1fr 1.1fr; align-items: center; gap: 3rem; }
    .hero-bg { background: radial-gradient(circle at 30% 40%, #0B3D2E 5%, #1A1A1A 90%); border-radius: 0 0 3rem 3rem; }
    .hero-image-wrapper img { border-radius: 0 0 1.5rem 0; object-fit: cover; height: 100%; width: 100%; }

    /* 案例瀑布 (Masonry形象版) */
    .case-masonry { columns: 3; gap: 1.5rem; }
    .case-card { break-inside: avoid; margin-bottom: 1.5rem; border-radius: var(--radius); overflow: hidden; position: relative; box-shadow: var(--shadow-card); transition: var(--transition); }
    .case-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-hover); }
    .card-img { position: relative; }
    .card-img img { display: block; width: 100%; object-fit: cover; aspect-ratio: 4/3; }
    .card-overlay { position: absolute; bottom:0; left:0; width:100%; padding:1rem; background: linear-gradient(transparent, rgba(0,0,0,0.75)); }
    .tag { background: var(--accent); color: var(--primary); padding: 0.3rem 0.8rem; border-radius: 30px; font-weight: 700; font-size: 0.75rem; }

    .compare-table { display: grid; grid-template-columns: 1fr 2px 1fr; background: white; border-radius: var(--radius-lg); overflow: hidden; box-shadow: var(--shadow-card); }
    .compare-col { padding: 2.5rem; }
    .compare-divider { background: var(--border-light); }
    .popular-badge { background: var(--accent); color: #1a1a1a; font-weight: 800; padding: 0.2rem 1rem; border-radius: 20px; font-size:0.8rem; margin-left:0.8rem; }

    .faq-block details { background: white; border-radius: var(--radius); padding: 1rem 1.5rem; margin-bottom: 0.8rem; box-shadow: 0 2px 10px rgba(0,0,0,0.03); }
    .footer { background: var(--primary); color: #d1e8d4; padding: 4rem 0 2rem; }

    @media (max-width:992px) { .case-masonry{columns:2;} .compare-table{grid-template-columns:1fr;}}
    @media (max-width:768px) {
      .hero .grid { grid-template-columns: 1fr; }
      .feature-grid { grid-template-columns: 1fr 1fr; }
      .case-masonry{columns:1;}
    }
    @media (max-width:560px) { .feature-grid{grid-template-columns:1fr;} }

.card-feat{background:white;padding:2rem;border-radius:var(--radius);box-shadow:0 6px 16px rgba(0,0,0,0.05);transition:var(--transition);}
.card-feat:hover{transform:translateY(-5px);}.card-feat i{margin-bottom:1rem;}