/* roulang page: index */
:root {
      --primary: #1A1A2E;
      --accent: #E94560;
      --accent-hover: #D63850;
      --bg: #F9F9FB;
      --dark-bg: #0F0F1A;
      --text: #1A1A2E;
      --text-secondary: #5C5C70;
      --text-light: #FFFFFF;
      --text-muted: #B0B0C0;
      --border: #E2E2EC;
      --card-bg: #FFFFFF;
      --shadow-sm: 0 2px 12px rgba(26,26,46,0.06);
      --shadow-hover: 0 8px 30px rgba(26,26,46,0.12);
      --radius-lg: 12px;
      --radius-md: 8px;
      --font-title: 'Noto Sans SC', 'PingFang SC', sans-serif;
      --font-body: 'Inter', 'SF Pro Text', sans-serif;
      --max-width: 1280px;
      --nav-height: 72px;
    }

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

    html {
      scroll-behavior: smooth;
    }

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

    h1, h2, h3 {
      font-family: var(--font-title);
      letter-spacing: -0.02em;
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-weight: 600;
      transition: all 0.25s ease;
    }

    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
      width: 100%;
    }

    /* 导航 */
    .nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      height: var(--nav-height);
      background: transparent;
      backdrop-filter: blur(0px);
      transition: background 0.3s, backdrop-filter 0.3s, box-shadow 0.3s;
    }

    .nav.scrolled {
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      box-shadow: 0 1px 8px rgba(0,0,0,0.04);
    }

    .nav .container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
    }

    .logo {
      font-family: var(--font-title);
      font-weight: 700;
      font-size: 22px;
      color: var(--text-light);
      transition: color 0.3s;
      letter-spacing: -0.01em;
      display: flex;
      align-items: center;
      gap: 4px;
    }

    .nav.scrolled .logo {
      color: var(--primary);
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 36px;
      font-weight: 500;
      font-size: 15px;
    }

    .nav-links a {
      color: var(--text-light);
      transition: color 0.2s;
      position: relative;
    }

    .nav.scrolled .nav-links a {
      color: var(--text);
    }

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

    .btn-primary {
      background: var(--accent);
      color: white;
      padding: 12px 28px;
      border-radius: var(--radius-md);
      font-weight: 600;
      font-size: 15px;
      box-shadow: 0 4px 12px rgba(233,69,96,0.25);
    }

    .btn-primary:hover {
      background: var(--accent-hover);
      box-shadow: 0 6px 20px rgba(233,69,96,0.4);
      transform: scale(1.03);
    }

    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 12px 28px;
      border-radius: var(--radius-md);
      font-weight: 600;
    }

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

    .btn-outline-light {
      background: transparent;
      border: 2px solid white;
      color: white;
      padding: 12px 28px;
      border-radius: var(--radius-md);
      font-weight: 600;
    }

    .btn-outline-light:hover {
      background: white;
      color: var(--primary);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      z-index: 1001;
    }

    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--text-light);
      transition: 0.3s;
    }

    .nav.scrolled .hamburger span {
      background: var(--primary);
    }

    /* Hero */
    #hero {
      background: var(--primary);
      min-height: 100vh;
      display: flex;
      align-items: center;
      padding-top: var(--nav-height);
      position: relative;
      overflow: hidden;
    }

    .hero-grid {
      display: flex;
      align-items: center;
      gap: 48px;
      width: 100%;
    }

    .hero-left {
      flex: 0 0 55%;
      color: var(--text-light);
    }

    .hero-left h1 {
      font-size: clamp(36px, 5vw, 54px);
      font-weight: 700;
      line-height: 1.2;
      margin-bottom: 24px;
    }

    .hero-left .subtitle {
      font-size: 18px;
      color: rgba(255,255,255,0.7);
      margin-bottom: 36px;
      max-width: 480px;
    }

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

    .hero-right {
      flex: 0 0 45%;
      position: relative;
      display: flex;
      justify-content: center;
      animation: float 4s ease-in-out infinite;
    }

    .hero-right img {
      max-width: 100%;
      border-radius: var(--radius-lg);
      filter: drop-shadow(0 20px 40px rgba(0,0,0,0.3));
    }

    .hero-glow {
      position: absolute;
      width: 350px;
      height: 350px;
      background: radial-gradient(circle, rgba(233,69,96,0.25) 0%, transparent 70%);
      border-radius: 50%;
      top: -50px;
      right: -60px;
      pointer-events: none;
    }

    @keyframes float {
      0% { transform: translateY(0); }
      50% { transform: translateY(-12px); }
      100% { transform: translateY(0); }
    }

    /* 亮点网格 */
    #advantages {
      padding: 100px 0;
    }

    .section-title {
      font-size: clamp(28px, 4vw, 36px);
      font-weight: 700;
      margin-bottom: 56px;
      text-align: center;
      color: var(--primary);
    }

    .advantages-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 32px;
      max-width: 900px;
      margin: 0 auto;
    }

    .advantage-item {
      background: var(--card-bg);
      padding: 36px 32px;
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-sm);
      transition: all 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    }

    .advantage-item:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }

    .advantage-item.full {
      grid-column: span 2;
      justify-self: center;
      max-width: 500px;
    }

    .advantage-icon {
      font-size: 40px;
      color: var(--accent);
      margin-bottom: 20px;
      line-height: 1;
    }

    .advantage-item h3 {
      font-size: 22px;
      margin-bottom: 12px;
      color: var(--primary);
    }

    .advantage-item p {
      color: var(--text-secondary);
      line-height: 1.7;
    }

    /* 服务卡片流 */
    #services {
      padding: 80px 0;
      background: #FFFFFF;
    }

    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }

    .service-card {
      background: var(--card-bg);
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-sm);
      overflow: hidden;
      transition: all 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
      display: flex;
      flex-direction: column;
    }

    .service-card:hover {
      transform: translateY(-8px);
      box-shadow: var(--shadow-hover);
    }

    .service-card.wide {
      grid-column: span 2;
    }

    .service-img {
      height: 200px;
      overflow: hidden;
    }

    .service-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      filter: grayscale(25%);
      transition: 0.4s ease;
    }

    .service-card:hover .service-img img {
      filter: grayscale(0%);
      transform: scale(1.05);
    }

    .service-body {
      padding: 28px 24px;
    }

    .service-body h3 {
      font-size: 20px;
      margin-bottom: 10px;
      color: var(--primary);
    }

    .service-body p {
      color: var(--text-secondary);
      font-size: 15px;
    }

    /* 案例瀑布 */
    #cases {
      padding: 90px 0;
    }

    .cases-columns {
      columns: 2;
      column-gap: 28px;
    }

    .case-item {
      break-inside: avoid;
      margin-bottom: 28px;
      background: var(--card-bg);
      border-radius: var(--radius-lg);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: 0.3s;
    }

    .case-item:hover {
      box-shadow: var(--shadow-hover);
    }

    .case-img img {
      width: 100%;
      display: block;
      filter: grayscale(35%);
      transition: 0.4s;
    }

    .case-item:hover .case-img img {
      filter: grayscale(0%);
    }

    .case-info {
      padding: 20px 24px;
    }

    .case-info h3 {
      font-size: 20px;
      margin-bottom: 8px;
    }

    .tags {
      display: flex;
      gap: 8px;
      flex-wrap: wrap;
      margin-bottom: 8px;
    }

    .tag {
      background: #F0F0F5;
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 12px;
      font-weight: 500;
      color: var(--text-secondary);
    }

    /* 对比 */
    #comparison {
      padding: 80px 0;
      background: #FFFFFF;
    }

    .comparison-wrapper {
      display: flex;
      gap: 32px;
      align-items: stretch;
      max-width: 900px;
      margin: 0 auto;
    }

    .comp-col {
      flex: 1;
      padding: 36px 28px;
      border-radius: var(--radius-lg);
    }

    .comp-col.old {
      background: rgba(0,0,0,0.02);
    }

    .comp-col.new {
      background: rgba(46,204,113,0.04);
    }

    .comp-col h3 {
      font-size: 22px;
      margin-bottom: 20px;
      text-align: center;
    }

    .comp-list {
      list-style: none;
    }

    .comp-list li {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-bottom: 18px;
      font-size: 16px;
    }

    .icon-fail {
      color: #E94560;
      font-weight: 700;
    }

    .icon-success {
      color: #2ECC71;
      font-weight: 700;
    }

    /* FAQ */
    #faq {
      padding: 80px 0;
      max-width: 800px;
      margin: 0 auto;
    }

    .faq-item {
      border-bottom: 1px solid var(--border);
    }

    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 22px 0;
      font-weight: 600;
      font-size: 18px;
      cursor: pointer;
      color: var(--primary);
    }

    .faq-arrow {
      transition: 0.3s;
      color: var(--accent);
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.3s;
      color: var(--text-secondary);
      padding: 0 0;
    }

    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }

    .faq-item.open .faq-arrow {
      transform: rotate(180deg);
    }

    /* CTA */
    #cta {
      background: var(--dark-bg);
      padding: 100px 24px;
      text-align: center;
    }

    #cta h2 {
      color: white;
      font-size: 36px;
      margin-bottom: 20px;
    }

    #cta p {
      color: var(--text-muted);
      margin-bottom: 36px;
    }

    .btn-cta-large {
      background: var(--accent);
      color: white;
      padding: 18px 56px;
      border-radius: var(--radius-md);
      font-size: 18px;
      font-weight: 700;
      transition: 0.3s;
    }

    .btn-cta-large:hover {
      background: var(--accent-hover);
      box-shadow: 0 0 30px rgba(233,69,96,0.65);
      transform: scale(1.02);
    }

    /* 页脚 */
    #footer {
      background: var(--dark-bg);
      color: var(--text-muted);
      padding: 64px 0 24px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 36px;
      margin-bottom: 40px;
    }

    .footer-brand .logo {
      color: white;
      margin-bottom: 12px;
      display: block;
    }

    .footer-links a {
      display: block;
      margin-bottom: 8px;
      color: var(--text-muted);
    }

    .footer-links a:hover {
      color: var(--accent);
    }

    .social-icons i {
      font-size: 20px;
      margin-right: 16px;
      color: var(--text-muted);
      transition: 0.2s;
    }

    .social-icons i:hover {
      color: var(--accent);
    }

    .copyright {
      border-top: 1px solid rgba(255,255,255,0.1);
      padding-top: 20px;
      text-align: center;
      font-size: 13px;
    }

    /* 移动菜单 */
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 75%;
        height: 100vh;
        background: var(--primary);
        flex-direction: column;
        justify-content: center;
        gap: 32px;
        transition: 0.4s;
      }
      .nav-links.active {
        right: 0;
      }
      .hamburger {
        display: flex;
      }
      .hero-grid {
        flex-direction: column;
      }
      .advantages-grid {
        grid-template-columns: 1fr;
      }
      .advantage-item.full {
        grid-column: span 1;
      }
      .services-grid {
        grid-template-columns: 1fr;
      }
      .service-card.wide {
        grid-column: span 1;
      }
      .cases-columns {
        columns: 1;
      }
      .comparison-wrapper {
        flex-direction: column;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }