/* roulang page: index */
:root {
      --primary: #0F4C3A;
      --primary-dark: #0A3A2C;
      --accent: #D9A066;
      --bg: #FAFAF8;
      --bg-alt: #F0EFE9;
      --text-heading: #1A1A1A;
      --text-body: #4A4A4A;
      --text-muted: #7A7A7A;
      --white: #FFFFFF;
      --footer-bg: #1A1A1A;
      --footer-text: #B0B0B0;
      --radius: 12px;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-hover: 0 12px 32px rgba(15,76,58,0.08);
      --transition: all 0.3s cubic-bezier(0.25,0.8,0.25,1.2);
      --gap: 2rem;
    }
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: 'PingFang SC','Microsoft YaHei','Helvetica Neue',sans-serif;
      background: var(--bg);
      color: var(--text-body);
      font-weight: 400;
      font-size: 1rem;
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }
    a { text-decoration: none; color: inherit; transition: var(--transition); }
    img { max-width: 100%; height: auto; display: block; }
    h1, h2, h3, h4, h5, h6 { font-weight: 600; color: var(--text-heading); line-height: 1.3; letter-spacing: 0.02em; }
    h1 { font-size: 2.75rem; }
    h2 { font-size: 2.25rem; font-weight: 600; }
    h3 { font-size: 1.5rem; font-weight: 600; }
    h4 { font-size: 1.25rem; font-weight: 600; color: var(--text-heading); }

    .container { max-width: 1200px; margin: 0 auto; padding: 0 1.5rem; }

    /* 导航 */
    #header {
      position: fixed; top: 0; left: 0; width: 100%; z-index: 1000;
      height: 72px; display: flex; align-items: center;
      background: transparent; border-bottom: 1px solid transparent;
      transition: background 0.4s ease, border-color 0.4s ease, backdrop-filter 0.4s ease;
    }
    #header.scrolled {
      background: rgba(250,250,248,0.92); backdrop-filter: blur(12px);
      border-bottom: 1px solid #E8E7E2;
    }
    .header-inner {
      display: flex; align-items: center; justify-content: space-between;
      width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 1.5rem;
    }
    .logo a {
      font-size: 1.6rem; font-weight: 700; color: var(--primary);
      letter-spacing: 0.05em; display: flex; align-items: center; gap: 0.4rem;
    }
    .logo .signal-icon { font-size: 1.8rem; color: var(--accent); }
    .nav-links { display: flex; align-items: center; gap: 2.2rem; list-style: none; }
    .nav-links a {
      font-weight: 500; font-size: 0.95rem; letter-spacing: 0.03em;
      color: var(--text-heading); position: relative; padding: 0.25rem 0;
    }
    .nav-links a::after {
      content: ''; position: absolute; bottom: 0; left: 50%; width: 0; height: 2px;
      background: var(--primary); transition: all 0.25s ease; transform: translateX(-50%);
    }
    .nav-links a:hover { color: var(--primary); }
    .nav-links a:hover::after { width: 100%; }
    .nav-cta a {
      background: var(--primary); color: var(--white); padding: 0.6rem 1.5rem;
      border-radius: 8px; font-weight: 600; font-size: 0.9rem;
      transition: var(--transition);
    }
    .nav-cta a:hover { background: var(--primary-dark); }
    .hamburger { display: none; background: none; border: none; font-size: 1.5rem; color: var(--text-heading); cursor: pointer; }
    .mobile-menu { display: none; position: fixed; top: 72px; left: 0; width: 100%; background: rgba(250,250,248,0.98); backdrop-filter: blur(16px); flex-direction: column; padding: 1.5rem; gap: 1.2rem; z-index: 999; }
    .mobile-menu a { font-weight: 600; font-size: 1.1rem; color: var(--text-heading); border-bottom: 1px solid #E8E7E2; padding-bottom: 0.8rem; }
    .mobile-menu .nav-cta-mobile a { background: var(--primary); color: white; display: inline-block; padding: 0.75rem 2rem; border-radius: 8px; text-align: center; }

    /* 板块间距 */
    section { padding: 5rem 0; }
    .section-alt { background: var(--bg-alt); }
    .section-title { text-align: center; margin-bottom: 3rem; }
    .section-subtitle { font-weight: 400; font-size: 1.125rem; color: var(--text-muted); margin-top: 0.5rem; }

    /* Hero */
    #hero { padding: 8rem 0 5rem; background: linear-gradient(135deg, #FAFAF8 0%, #F0EFE9 100%); position: relative; overflow: hidden; }
    #hero::before { content: ''; position: absolute; top: -80px; right: -80px; width: 320px; height: 320px; background: radial-gradient(circle, rgba(217,160,102,0.08) 0%, transparent 70%); border-radius: 50%; }
    .hero-grid { display: flex; align-items: center; gap: 2rem; }
    .hero-left { flex: 1; }
    .hero-right { flex: 1; position: relative; }
    .hero-right img { width: 100%; border-radius: var(--radius); box-shadow: var(--shadow-hover); object-fit: cover; aspect-ratio: 16/10; }
    .hero-badges { display: flex; gap: 1.5rem; margin: 1.5rem 0 2rem; }
    .badge-item { display: flex; align-items: center; gap: 0.4rem; font-size: 0.9rem; font-weight: 500; color: var(--primary); background: rgba(15,76,58,0.06); padding: 0.4rem 1rem; border-radius: 20px; }
    .btn-group { display: flex; gap: 1rem; flex-wrap: wrap; }
    .btn-primary {
      background: var(--primary); color: var(--white); border: none;
      padding: 0.85rem 2.2rem; border-radius: 8px; font-weight: 600;
      transition: var(--transition); display: inline-block; cursor: pointer;
    }
    .btn-primary:hover { background: var(--primary-dark); box-shadow: inset 0 0 8px rgba(0,0,0,0.2); color: white; }
    .btn-outline {
      background: transparent; color: var(--primary); border: 1.5px solid var(--primary);
      padding: 0.85rem 2.2rem; border-radius: 8px; font-weight: 600;
      transition: var(--transition); display: inline-block; cursor: pointer;
    }
    .btn-outline:hover { background: var(--primary); color: white; }

    /* 卡片 */
    .card-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--gap); }
    .card {
      background: var(--white); border-radius: var(--radius); padding: 2rem;
      box-shadow: var(--shadow-sm); transition: var(--transition);
    }
    .card:hover { box-shadow: var(--shadow-hover); transform: translateY(-4px); }
    .card-icon { font-size: 2.5rem; color: var(--primary); margin-bottom: 1.2rem; }
    .card h4 { margin-bottom: 0.8rem; }
    .feature-list { list-style: none; margin-top: 1rem; }
    .feature-list li { display: flex; align-items: flex-start; gap: 0.5rem; font-size: 0.9rem; color: var(--text-body); margin-bottom: 0.5rem; }
    .feature-list li i { color: var(--primary); font-size: 0.9rem; margin-top: 0.2rem; }

    /* 数据 */
    .stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--gap); text-align: center; }
    .stat-number { font-weight: 700; font-size: 2.5rem; color: var(--primary); line-height: 1.2; }
    .stat-label { font-size: 0.95rem; color: var(--text-muted); margin-top: 0.4rem; }

    /* 案例 */
    .case-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--gap); }
    .case-card { background: var(--white); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow-sm); transition: var(--transition); }
    .case-card:hover { box-shadow: var(--shadow-hover); transform: translateY(-4px); }
    .case-card img { width: 100%; height: 220px; object-fit: cover; transition: transform 0.3s ease; }
    .case-card:hover img { transform: scale(1.03); }
    .case-body { padding: 1.5rem; }
    .case-tag { display: inline-block; background: var(--bg-alt); color: var(--primary); font-size: 0.8rem; padding: 0.2rem 0.8rem; border-radius: 12px; margin-bottom: 0.6rem; }

    /* 解决方案 */
    .solution-block { display: flex; align-items: center; gap: 3rem; margin-bottom: 4rem; }
    .solution-block.reverse { flex-direction: row-reverse; }
    .solution-img, .solution-text { flex: 1; }
    .solution-img img { border-radius: var(--radius); box-shadow: var(--shadow-sm); width: 100%; }
    .solution-list { list-style: none; margin-top: 1rem; }
    .solution-list li { display: flex; align-items: flex-start; gap: 0.6rem; margin-bottom: 0.6rem; }
    .solution-list li i { color: var(--primary); }

    /* FAQ */
    .accordion-item { background: var(--white); border-radius: var(--radius); margin-bottom: 0.8rem; box-shadow: var(--shadow-sm); overflow: hidden; }
    .accordion-question {
      width: 100%; background: none; border: none; text-align: left; padding: 1.3rem 2rem; font-weight: 600; font-size: 1.05rem; color: var(--text-heading); cursor: pointer; display: flex; justify-content: space-between; align-items: center;
    }
    .accordion-answer { max-height: 0; overflow: hidden; transition: max-height 0.4s ease; padding: 0 2rem; }
    .accordion-answer p { padding-bottom: 1.3rem; color: var(--text-body); }
    .accordion-item.open .accordion-answer { max-height: 200px; }
    .accordion-icon { transition: transform 0.3s ease; color: var(--primary); }
    .accordion-item.open .accordion-icon { transform: rotate(45deg); }

    /* CTA */
    #cta { background: var(--primary); color: white; text-align: center; position: relative; }
    #cta h2 { color: white; }
    #cta .btn-white { background: white; color: var(--primary); border: 2px solid white; padding: 0.85rem 2.8rem; border-radius: 8px; font-weight: 700; transition: var(--transition); display: inline-block; }
    #cta .btn-white:hover { background: transparent; color: white; }

    /* 页脚 */
    #footer { background: var(--footer-bg); color: var(--footer-text); padding: 3rem 0 1.5rem; }
    .footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr 1fr; gap: 2rem; margin-bottom: 2rem; }
    .footer-brand .footer-logo { font-size: 1.5rem; font-weight: 700; color: white; margin-bottom: 0.6rem; }
    .footer-links h4 { color: white; font-size: 1rem; margin-bottom: 0.8rem; }
    .footer-links a { display: block; color: var(--footer-text); margin-bottom: 0.4rem; font-size: 0.9rem; }
    .footer-links a:hover { color: var(--accent); }
    .footer-bottom { border-top: 1px solid #333; padding-top: 1.5rem; text-align: center; font-size: 0.85rem; }

    /* 响应式 */
    @media (max-width: 1024px) {
      h1 { font-size: 2.2rem; }
      .card-grid { grid-template-columns: 1fr 1fr; }
      .stats-grid { grid-template-columns: 1fr 1fr; }
      .case-grid { grid-template-columns: 1fr; }
      .solution-block { flex-direction: column; gap: 1.5rem; }
      .solution-block.reverse { flex-direction: column; }
    }
    @media (max-width: 768px) {
      .nav-links, .nav-cta { display: none; }
      .hamburger { display: block; }
      .mobile-menu.open { display: flex; }
      #hero { padding: 6rem 0 3rem; }
      .hero-grid { flex-direction: column; }
      .card-grid { grid-template-columns: 1fr; }
      h2 { font-size: 1.8rem; }
      section { padding: 3rem 0; }
      .btn-group .btn-primary, .btn-group .btn-outline { width: 100%; text-align: center; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }
    @media (max-width: 520px) {
      .hero-badges { flex-wrap: wrap; }
      .stats-grid { grid-template-columns: 1fr 1fr; gap: 1rem; }
      .stat-number { font-size: 2rem; }
      .footer-grid { grid-template-columns: 1fr; }
    }