/* roulang page: index */
:root {
      --primary: #E9402B;
      --primary-dark: #C8301F;
      --secondary-dark: #1A1D2E;
      --secondary-light: #F5F0EB;
      --accent: #00E5A1;
      --text-dark: #1E1E1E;
      --text-light: #EAEAEA;
      --border-light: #E0DCD7;
      --border-dark: rgba(255,255,255,0.08);
      --card-bg: #FFFFFF;
      --card-dark-bg: rgba(255,255,255,0.04);
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --shadow-card: 0 1px 3px rgba(0,0,0,0.04), 0 4px 12px rgba(0,0,0,0.06);
      --shadow-card-hover: 0 4px 8px rgba(0,0,0,0.06), 0 12px 24px rgba(0,0,0,0.1);
      --font-title: 'PingFang SC', 'Noto Sans SC', 'Microsoft YaHei', sans-serif;
      --font-body: 'PingFang SC', 'Noto Sans SC', 'Inter', system-ui, -apple-system, sans-serif;
      --container-max: 1280px;
      --section-padding: 100px;
      --card-padding: 28px;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: var(--font-body);
      background-color: var(--secondary-light);
      color: var(--text-dark);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s;
    }

    button, .btn {
      cursor: pointer;
      font-family: var(--font-body);
      border: none;
      background: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
      font-weight: 600;
    }

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

    /* 导航 */
    .header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-light);
      transition: box-shadow 0.3s;
    }
    .header.scrolled {
      box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    }
    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 70px;
    }
    .logo {
      font-family: var(--font-title);
      font-weight: 800;
      font-size: 1.8rem;
      color: var(--secondary-dark);
      letter-spacing: -0.5px;
      display: flex;
      align-items: baseline;
    }
    .logo .accent-dot {
      color: var(--primary);
      font-size: 2.2rem;
      margin-left: 2px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      font-weight: 500;
      font-size: 1rem;
      color: var(--text-dark);
      position: relative;
      padding: 4px 0;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width 0.25s;
    }
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 12px 28px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      box-shadow: 0 4px 10px rgba(233,64,43,0.25);
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: translateY(-1px);
      box-shadow: 0 8px 18px rgba(232,64,43,0.35);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 12px 28px;
      border-radius: var(--radius-sm);
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
    }
    .btn-ghost {
      background: transparent;
      border: 2px solid white;
      color: white;
      padding: 12px 28px;
      border-radius: var(--radius-sm);
    }
    .btn-ghost:hover {
      background: white;
      color: var(--secondary-dark);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
    }
    .hamburger span {
      width: 25px;
      height: 2.5px;
      background: var(--secondary-dark);
      border-radius: 4px;
      transition: 0.2s;
    }

    /* Hero */
    .hero {
      background: linear-gradient(135deg, #F5F0EB 0%, #FFF4F0 100%);
      padding: 60px 0 80px;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-content h1 {
      font-family: var(--font-title);
      font-size: 3rem;
      font-weight: 800;
      line-height: 1.2;
      letter-spacing: -0.02em;
      color: var(--secondary-dark);
      margin-bottom: 20px;
    }
    .hero-content .sub {
      font-size: 1.125rem;
      color: #4A4A4A;
      margin-bottom: 32px;
      max-width: 90%;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-visual {
      position: relative;
      border-radius: var(--radius-lg);
      overflow: hidden;
      background: var(--secondary-dark);
    }
    .hero-visual img {
      width: 100%;
      height: auto;
      object-fit: cover;
      aspect-ratio: 4/3;
    }
    .hero-overlay {
      position: absolute;
      inset: 0;
      background: linear-gradient(135deg, rgba(233,64,43,0.15) 0%, rgba(26,29,46,0.6) 100%);
      display: flex;
      align-items: flex-end;
      padding: 24px;
    }

    /* 通用板块 */
    .section {
      padding: var(--section-padding) 0;
    }
    .section-dark {
      background: var(--secondary-dark);
      color: var(--text-light);
    }
    .section-title {
      font-family: var(--font-title);
      font-size: 2.25rem;
      font-weight: 700;
      margin-bottom: 48px;
      text-align: center;
    }

    /* 亮点网格 2x3 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .feature-card {
      background: var(--card-bg);
      padding: var(--card-padding);
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      text-align: center;
      transition: transform 0.2s, box-shadow 0.2s;
    }
    .feature-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    .feature-icon {
      font-size: 2.5rem;
      margin-bottom: 16px;
      color: var(--primary);
    }
    .feature-card h3 {
      font-size: 1.3rem;
      font-weight: 600;
      margin-bottom: 8px;
    }
    .feature-card p {
      font-size: 0.9rem;
      color: #5A5A5A;
    }

    /* 瀑布流案例 */
    .masonry {
      columns: 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 0.2s;
    }
    .masonry-item:hover {
      transform: translateY(-4px);
    }
    .masonry-img {
      position: relative;
      aspect-ratio: 16/9;
      background: #e0e0e0;
    }
    .masonry-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
    }
    .masonry-img .gradient-overlay {
      position: absolute;
      inset: 0;
      background: linear-gradient(0deg, rgba(0,0,0,0.5) 0%, transparent 60%);
      opacity: 0;
      transition: 0.3s;
      display: flex;
      align-items: flex-end;
      padding: 16px;
      color: white;
      font-weight: 600;
    }
    .masonry-item:hover .gradient-overlay {
      opacity: 1;
    }
    .masonry-info {
      padding: 16px;
    }
    .masonry-info h3 {
      font-size: 1.1rem;
      font-weight: 700;
      margin-bottom: 6px;
    }
    .masonry-tags {
      display: flex;
      gap: 8px;
      font-size: 0.75rem;
      color: #777;
    }

    /* 对比区 */
    .compare-grid {
      display: grid;
      grid-template-columns: 1fr auto 1fr;
      gap: 24px;
      align-items: center;
    }
    .compare-col {
      background: white;
      border-radius: var(--radius-md);
      padding: 32px;
      box-shadow: var(--shadow-card);
    }
    .compare-col.left {
      border-left: 4px solid #9E9E9E;
    }
    .compare-col.right {
      border-left: 4px solid var(--primary);
    }
    .compare-col h3 {
      font-size: 1.6rem;
      margin-bottom: 20px;
    }
    .compare-list {
      list-style: none;
    }
    .compare-list li {
      display: flex;
      align-items: center;
      gap: 10px;
      margin-bottom: 14px;
    }
    .vs-badge {
      font-weight: 800;
      font-size: 2rem;
      color: var(--primary);
    }
    .check { color: var(--accent); font-weight: bold; }
    .cross { color: #B0B0B0; }

    /* 数据区 */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
      text-align: center;
    }
    .stat-item .number {
      font-size: 3.5rem;
      font-weight: 800;
      color: var(--accent);
      line-height: 1.1;
    }
    .stat-item .label {
      color: #CCCCCC;
      font-size: 1rem;
      margin-top: 8px;
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    details.faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
    }
    details.faq-item summary {
      font-weight: 600;
      font-size: 1.1rem;
      cursor: pointer;
      list-style: none;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    details.faq-item summary::-webkit-details-marker { display: none; }
    .faq-answer {
      padding-top: 12px;
      color: #4A4A4A;
    }

    /* CTA 横幅 */
    .cta-banner {
      text-align: center;
      padding: 80px 0;
    }
    .cta-banner h2 {
      font-size: 2.5rem;
      font-weight: 700;
      margin-bottom: 16px;
    }
    .cta-banner p {
      font-size: 1.2rem;
      margin-bottom: 32px;
      opacity: 0.9;
    }

    /* 页脚 */
    .footer {
      background: var(--secondary-dark);
      color: #AAAAAA;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer h4 {
      color: white;
      margin-bottom: 16px;
    }
    .footer a {
      color: #AAAAAA;
      display: block;
      margin-bottom: 8px;
      font-size: 0.95rem;
    }
    .footer a:hover { color: var(--accent); }
    .copyright {
      margin-top: 40px;
      text-align: center;
      font-size: 0.85rem;
      border-top: 1px solid rgba(255,255,255,0.1);
      padding-top: 24px;
    }

    @media (max-width: 1024px) {
      .features-grid { grid-template-columns: repeat(2, 1fr); }
      .masonry { columns: 2; }
      .compare-grid { grid-template-columns: 1fr; }
      .vs-badge { display: none; }
      .stats-grid { grid-template-columns: repeat(2, 1fr); }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }

    @media (max-width: 768px) {
      :root { --section-padding: 64px; }
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero-grid { grid-template-columns: 1fr; }
      .hero-visual { order: -1; }
      .features-grid { grid-template-columns: 1fr; }
      .masonry { columns: 1; }
      .footer-grid { grid-template-columns: 1fr; }
      h1 { font-size: 2.2rem !important; }
    }

    .mobile-menu {
      display: none;
      position: fixed;
      top: 70px;
      left: 0;
      right: 0;
      bottom: 0;
      background: white;
      flex-direction: column;
      padding: 32px;
      gap: 24px;
      font-size: 1.2rem;
      z-index: 40;
    }
    .mobile-menu.open { display: flex; }