/* roulang page: index */
:root {
      --color-primary: #0B0C0E;
      --color-accent: #D4AF37;
      --color-bg: #FAFAFA;
      --color-card: #FFFFFF;
      --color-light-gray: #F5F5F5;
      --color-text-primary: #0B0C0E;
      --color-text-body: #2C2C2C;
      --color-text-muted: #7D7D7D;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui, -apple-system, sans-serif;
      --font-mono: "Inter", "SF Pro Display", "Helvetica Neue", sans-serif;
      --shadow-card: 0 1px 3px rgba(0,0,0,0.04), 0 1px 2px rgba(0,0,0,0.06);
      --shadow-card-hover: 0 4px 12px rgba(0,0,0,0.08);
      --radius-sm: 2px;
      --radius-md: 4px;
      --transition-base: 0.25s ease;
      --transition-smooth: 0.3s ease;
      --max-width: 1280px;
      --section-gap: 120px;
    }

    * {
      box-sizing: border-box;
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--color-bg);
      color: var(--color-text-body);
      margin: 0;
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

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

    a {
      color: inherit;
      text-decoration: none;
    }

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

    .container {
      max-width: var(--max-width);
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }

    /* 滚动渐现动画 */
    .fade-up {
      opacity: 0;
      transform: translateY(24px);
      transition: opacity 0.6s ease-out, transform 0.6s ease-out;
    }
    .fade-up.visible {
      opacity: 1;
      transform: translateY(0);
    }

    /* 导航样式 */
    .nav-link {
      font-size: 0.875rem;
      font-weight: 500;
      color: var(--color-text-muted);
      position: relative;
      padding-bottom: 4px;
      transition: color var(--transition-base);
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background-color: var(--color-accent);
      transition: width var(--transition-smooth);
    }
    .nav-link:hover,
    .nav-link.active {
      color: var(--color-text-primary);
    }
    .nav-link.active::after,
    .nav-link:hover::after {
      width: 100%;
    }

    .nav-divider {
      width: 1px;
      height: 16px;
      background-color: #E0E0E0;
      margin: 0 0.75rem;
    }

    /* 按钮样式 */
    .btn-primary {
      background-color: var(--color-primary);
      color: white;
      font-weight: 600;
      padding: 0.75rem 2.25rem;
      border-radius: var(--radius-sm);
      display: inline-block;
      text-align: center;
      transition: background-color var(--transition-base), color var(--transition-base);
      border: 1px solid transparent;
      letter-spacing: 0.02em;
      font-size: 1rem;
    }
    .btn-primary:hover {
      background-color: var(--color-accent);
      color: var(--color-primary);
      border-color: var(--color-accent);
    }

    .btn-text {
      color: var(--color-text-primary);
      font-weight: 500;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      border-bottom: 2px solid var(--color-accent);
      transition: opacity var(--transition-base);
      font-size: 1rem;
    }
    .btn-text:hover {
      opacity: 0.7;
    }

    /* 卡片悬停动效 */
    .hover-card {
      transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
      border: 1px solid transparent;
      background-color: var(--color-card);
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
    }
    .hover-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
      border-color: var(--color-accent);
      border-bottom: 2px solid var(--color-accent);
    }

    /* 案例瀑布流 */
    .masonry-grid {
      column-count: 3;
      column-gap: 24px;
    }
    .masonry-item {
      break-inside: avoid;
      margin-bottom: 24px;
      background: white;
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      overflow: hidden;
      transition: transform var(--transition-base), box-shadow var(--transition-base);
    }
    .masonry-item:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    .masonry-item img {
      transition: transform 0.4s ease;
    }
    .masonry-item:hover img {
      transform: scale(1.03);
    }
    .masonry-item .card-info {
      padding: 1.5rem;
    }

    /* FAQ手风琴 */
    .faq-item {
      border-bottom: 1px solid #E5E5E5;
      padding: 1.25rem 0;
      cursor: pointer;
    }
    .faq-question {
      font-weight: 600;
      font-size: 1.125rem;
      color: var(--color-text-primary);
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.4s ease;
      color: var(--color-text-muted);
      font-size: 1rem;
      line-height: 1.7;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-top: 0.75rem;
    }
    .faq-item.open .faq-icon {
      transform: rotate(180deg);
    }
    .faq-icon {
      transition: transform 0.3s ease;
      font-size: 1.25rem;
      color: var(--color-accent);
    }

    /* 表单单线样式 */
    .input-line {
      background: transparent;
      border: none;
      border-bottom: 1px solid #CCCCCC;
      padding: 0.75rem 0;
      width: 100%;
      outline: none;
      transition: border-color var(--transition-base);
      font-size: 1rem;
    }
    .input-line:focus {
      border-bottom-color: var(--color-accent);
    }

    @media (max-width: 1024px) {
      .masonry-grid {
        column-count: 2;
      }
    }
    @media (max-width: 768px) {
      :root {
        --section-gap: 80px;
      }
      .masonry-grid {
        column-count: 1;
      }
      .hero-right {
        height: 50vh !important;
      }
      .nav-desktop {
        display: none !important;
      }
      .mobile-menu-btn {
        display: block !important;
      }
    }

    @media (min-width: 769px) {
      .mobile-menu-btn {
        display: none !important;
      }
      .mobile-menu {
        display: none !important;
      }
    }