/* roulang page: index */
:root {
      --primary: #E93D2F;
      --primary-dark: #c6281a;
      --secondary: #0F172A;
      --white: #FFFFFF;
      --bg-light: #F8FAFC;
      --border-light: #E2E8F0;
      --text-muted: #64748B;
      --accent-yellow: #FBBF24;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", system-ui, -apple-system, sans-serif;
      --shadow-sm: 0 1px 3px rgba(15,23,42,0.04), 0 1px 2px rgba(15,23,42,0.06);
      --shadow-md: 0 4px 12px rgba(15,23,42,0.06), 0 2px 6px rgba(15,23,42,0.04);
      --shadow-lg: 0 10px 25px rgba(15,23,42,0.08), 0 4px 10px rgba(15,23,42,0.04);
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --transition: 250ms ease;
      --content-width: 1280px;
    }

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

    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--white);
      color: var(--secondary);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
      background: var(--bg-light);
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color var(--transition);
    }

    .container {
      max-width: var(--content-width);
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 按钮系统 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-weight: 600;
      padding: 14px 32px;
      border-radius: var(--radius-sm);
      transition: all 300ms ease-out;
      cursor: pointer;
      border: 2px solid transparent;
      line-height: 1.2;
      letter-spacing: 0.02em;
      min-width: 140px;
    }

    .btn-primary {
      background: var(--primary);
      color: var(--white);
      border-color: var(--primary);
    }

    .btn-primary:hover {
      background: var(--primary-dark);
      border-color: var(--primary-dark);
      box-shadow: 0 0 0 4px rgba(233,61,47,0.2);
      transform: translateY(-1px);
    }

    .btn-outline {
      background: transparent;
      color: var(--primary);
      border-color: var(--primary);
    }

    .btn-outline:hover {
      background: rgba(233,61,47,0.04);
      box-shadow: 0 0 0 4px rgba(233,61,47,0.1);
      transform: translateY(-1px);
    }

    .btn-white {
      background: var(--white);
      color: var(--secondary);
      border-color: transparent;
      font-weight: 700;
    }

    .btn-white:hover {
      background: #f1f5f9;
      box-shadow: 0 8px 18px rgba(0,0,0,0.12);
      transform: scale(1.02);
    }

    /* 导航 */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(8px);
      border-bottom: 1px solid transparent;
      transition: border-color 0.3s, box-shadow 0.3s;
      height: 72px;
      display: flex;
      align-items: center;
    }

    .site-header.scrolled {
      border-bottom: 1px solid var(--border-light);
      box-shadow: var(--shadow-sm);
    }

    .header-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }

    .logo {
      font-size: 1.7rem;
      font-weight: 800;
      letter-spacing: -0.02em;
      color: var(--secondary);
    }
    .logo span {
      color: var(--primary);
    }

    .nav-menu {
      display: flex;
      gap: 2rem;
      align-items: center;
    }

    .nav-menu a {
      font-weight: 500;
      font-size: 0.95rem;
      color: var(--secondary);
      position: relative;
      padding: 4px 0;
    }

    .nav-menu a::after {
      content: "";
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width 0.2s ease;
    }

    .nav-menu a:hover,
    .nav-menu a.active {
      color: var(--primary);
    }

    .nav-menu a.active::after {
      width: 100%;
    }

    .mobile-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 1.8rem;
      color: var(--secondary);
      cursor: pointer;
    }

    .mobile-drawer {
      position: fixed;
      top: 0;
      right: 0;
      width: 280px;
      height: 100vh;
      background: var(--secondary);
      transform: translateX(100%);
      transition: transform 0.3s ease;
      z-index: 100;
      padding: 32px 24px;
      display: flex;
      flex-direction: column;
      gap: 28px;
      box-shadow: -8px 0 20px rgba(0,0,0,0.15);
    }

    .mobile-drawer.open {
      transform: translateX(0);
    }
    
    .mobile-drawer a {
      color: #F8FAFC;
      font-size: 1.2rem;
      border-left: 3px solid transparent;
      padding-left: 12px;
    }
    .mobile-drawer a.active {
      border-left-color: var(--primary);
      color: var(--primary);
    }

    /* 区块间距 */
    section {
      padding: 100px 0;
    }

    @media (max-width: 768px) {
      section {
        padding: 80px 0;
      }
      .site-header {
        height: 60px;
      }
    }

    /* 首屏 Hero */
    .hero-grid {
      display: flex;
      align-items: center;
      min-height: 90vh;
      gap: 48px;
    }

    .hero-content {
      flex: 1;
    }

    .hero-content h1 {
      font-size: 3rem;
      font-weight: 800;
      letter-spacing: -0.02em;
      color: var(--secondary);
      line-height: 1.2;
      margin-bottom: 20px;
    }

    .hero-content .subtitle {
      font-size: 1.2rem;
      color: var(--text-muted);
      margin-bottom: 2rem;
    }

    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }

    .hero-image {
      flex: 1;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: var(--radius-lg);
      height: 460px;
      position: relative;
      box-shadow: var(--shadow-lg);
    }

    .hero-image::after {
      content: "";
      position: absolute;
      inset: 0;
      background: linear-gradient(135deg, rgba(15,23,42,0.3) 0%, rgba(0,0,0,0.1) 100%);
      border-radius: var(--radius-lg);
    }

    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column-reverse;
        min-height: auto;
      }
      .hero-image {
        width: 100%;
        height: 320px;
      }
      .hero-content h1 {
        font-size: 2.2rem;
      }
    }

    /* 亮点网格 */
    .highlights-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .highlight-card {
      background: var(--white);
      padding: 32px;
      border-radius: var(--radius-md);
      text-align: center;
      transition: all 0.3s;
      border: 1px solid var(--border-light);
    }
    .highlight-card:hover {
      background: #FFF5F5;
      transform: scale(1.02);
      border-color: var(--primary);
    }
    .highlight-number {
      font-size: 2.8rem;
      font-weight: 800;
      color: var(--primary);
    }

    /* 服务 */
    .services-layout {
      display: flex;
      gap: 24px;
    }
    .service-large {
      flex: 0 0 60%;
      background: url('/assets/images/coverpic/cover-1.webp') center/cover;
      border-radius: var(--radius-md);
      height: 400px;
      position: relative;
      display: flex;
      align-items: flex-end;
    }
    .service-large .overlay {
      background: linear-gradient(0deg, rgba(0,0,0,0.7) 0%, transparent 90%);
      padding: 28px;
      color: white;
      width: 100%;
    }
    .services-small {
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 24px;
    }

    /* 案例瀑布流 */
    .cases-masonry {
      columns: 3;
      column-gap: 24px;
    }
    .case-card {
      break-inside: avoid;
      margin-bottom: 24px;
      background: white;
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: all 0.3s;
    }
    .case-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-lg);
    }

    /* Scheme对比 */
    .scheme-scroll {
      display: flex;
      gap: 20px;
      overflow-x: auto;
      scroll-snap-type: x mandatory;
      padding-bottom: 10px;
    }
    .scheme-card {
      min-width: 260px;
      scroll-snap-align: start;
      background: white;
      border-radius: var(--radius-md);
      padding: 28px;
      border: 1px solid var(--border-light);
    }
    .scheme-card.recommend {
      background: var(--primary);
      color: white;
    }

    /* 页脚 */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1.5fr 1fr;
      gap: 32px;
    }
    @media (max-width: 768px) {
      .highlights-grid, .services-layout, .footer-grid {
        grid-template-columns: 1fr;
        display: block;
      }
      .cases-masonry { columns: 1; }
      .nav-menu { display: none; }
      .mobile-toggle { display: block; }
    }

    .fade-up {
      opacity: 0;
      transform: translateY(20px);
      transition: opacity 0.6s ease, transform 0.6s ease;
    }
    .fade-up.visible {
      opacity: 1;
      transform: translateY(0);
    }