/* roulang page: index */
/* 设计变量与全局重置 */
    :root {
      --primary: #3E2723;
      --primary-deeper: #2B1A16;
      --accent: #D4AF37;
      --bg-warm: #FDFBF7;
      --text-dark: #2C2C2C;
      --text-soft: #5A554B;
      --card-bg: #FFFFFF;
      --border-light: #E8E4D9;
      --border-soft: #F0EDE6;
      --emerald: #004D40;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-md: 0 12px 32px rgba(0,0,0,0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-pill: 20px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --font-mono: "Inter", "SF Pro Display", system-ui;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-warm);
      color: var(--text-dark);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      scroll-behavior: smooth;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.25s ease;
    }

    button, .btn {
      cursor: pointer;
      font-family: inherit;
    }

    /* 容器 */
    .container-custom {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }

    /* 导航 */
    .header-nav {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255,255,255,0.96);
      backdrop-filter: blur(12px);
      box-shadow: 0 1px 3px rgba(0,0,0,0.04);
      border-bottom: 1px solid var(--border-soft);
      padding: 0.75rem 0;
    }

    .nav-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      flex-wrap: wrap;
    }

    .logo-area {
      display: flex;
      align-items: center;
      gap: 0.5rem;
    }

    .logo-icon {
      font-size: 2rem;
      color: var(--primary);
      line-height: 1;
    }

    .logo-text {
      font-weight: 700;
      font-size: 1.5rem;
      letter-spacing: 0.5px;
      color: var(--primary);
      font-family: var(--font-mono);
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 2rem;
      font-weight: 500;
      color: var(--text-dark);
    }

    .nav-links a {
      position: relative;
      padding: 0.25rem 0;
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--primary);
      transition: width 0.25s ease;
    }

    .nav-links a:hover {
      color: var(--primary);
    }

    .nav-links a:hover::after {
      width: 100%;
    }

    .search-box {
      background: var(--bg-warm);
      border: 1px solid #E0DCD3;
      border-radius: var(--radius-pill);
      padding: 0.5rem 1.2rem;
      font-size: 0.9rem;
      color: var(--text-soft);
      outline: none;
      transition: border 0.25s;
      width: 180px;
    }

    .search-box:focus {
      border-color: var(--accent);
    }

    .btn-primary {
      background: var(--primary);
      color: white;
      border-radius: var(--radius-btn);
      padding: 0.7rem 2rem;
      font-weight: 600;
      border: none;
      transition: background 0.25s, box-shadow 0.25s;
      display: inline-block;
      text-align: center;
      box-shadow: 0 4px 10px rgba(62,39,35,0.2);
    }

    .btn-primary:hover {
      background: var(--primary-deeper);
      box-shadow: 0 8px 18px rgba(43,26,22,0.3);
    }

    .btn-outline {
      background: transparent;
      border: 1px solid var(--primary);
      color: var(--primary);
      border-radius: var(--radius-btn);
      padding: 0.7rem 2rem;
      font-weight: 600;
      transition: all 0.25s;
    }

    .btn-outline:hover {
      background: rgba(62,39,35,0.06);
    }

    /* 汉堡菜单移动端 */
    .mobile-menu-btn {
      display: none;
      background: none;
      border: none;
      font-size: 1.8rem;
      color: var(--primary);
    }

    /* 区块间距 */
    .section-space {
      padding: 5rem 0;
    }

    /* 卡片基础 */
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      transition: transform 0.3s ease, box-shadow 0.3s ease;
      padding: 2rem 1.5rem;
    }

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

    .accent-icon {
      color: var(--accent);
      font-size: 2rem;
      margin-bottom: 1rem;
    }

    /* 案例瀑布 */
    .masonry-grid {
      column-count: 3;
      column-gap: 1.5rem;
    }

    .masonry-item {
      break-inside: avoid;
      margin-bottom: 1.5rem;
      border-radius: var(--radius-card);
      overflow: hidden;
      background: white;
      box-shadow: var(--shadow-sm);
      transition: all 0.3s;
    }

    .masonry-item:hover img {
      transform: scale(1.04);
    }

    .masonry-item img {
      transition: transform 0.4s ease;
      width: 100%;
      display: block;
    }

    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 1.2rem 0;
    }

    .faq-question {
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--primary);
      font-size: 1.1rem;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.35s;
      color: var(--text-soft);
    }

    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-top: 0.8rem;
    }

    .footer-dark {
      background: var(--primary-deeper);
      color: #D9D0C7;
    }

    @media (max-width: 1024px) {
      .masonry-grid {
        column-count: 2;
      }
    }

    @media (max-width: 768px) {
      .nav-links, .search-box {
        display: none;
      }
      .mobile-menu-btn {
        display: block;
      }
      .masonry-grid {
        column-count: 1;
      }
      .hero-flex {
        flex-direction: column-reverse;
      }
      .grid-3col {
        grid-template-columns: 1fr;
      }
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }

    @media (max-width: 520px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }