/* roulang page: index */
/* 设计变量与全局重置 */
    :root {
      --color-primary: #6C3CF0;
      --color-secondary: #00E5FF;
      --color-accent: #FF3A6F;
      --color-bg: #0B0E1A;
      --color-surface: rgba(19, 23, 43, 0.8);
      --color-text: #FFFFFF;
      --color-text-muted: #B0B8D0;
      --color-text-soft: #7A83A0;
      --radius-card: 16px;
      --radius-btn: 8px;
      --radius-tag: 4px;
      --shadow-card: 0 8px 32px rgba(0,0,0,0.4), 0 0 1px rgba(108,60,240,0.3);
      --font-heading: 'DIN Alternate', 'PingFang SC', 'Microsoft YaHei', sans-serif;
      --font-body: 'Inter', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-body);
      background-color: var(--color-bg);
      color: var(--color-text-muted);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 16px;
      }
    }
    /* 字体预设 */
    h1, h2, h3, .font-heading {
      font-family: var(--font-heading);
      font-weight: 600;
    }
    /* 按钮全局 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: all 0.3s ease;
      cursor: pointer;
      border: none;
      font-size: 16px;
      padding: 12px 28px;
    }
    .btn-primary {
      background: var(--color-primary);
      color: white;
      box-shadow: 0 4px 12px rgba(108,60,240,0.4);
    }
    .btn-primary:hover {
      background: #7D54FF;
      box-shadow: 0 0 20px rgba(108,60,240,0.6);
      transform: translateY(-2px);
    }
    .btn-secondary {
      background: transparent;
      border: 1.5px solid var(--color-secondary);
      color: var(--color-secondary);
    }
    .btn-secondary:hover {
      background: rgba(0, 229, 255, 0.08);
      box-shadow: 0 0 16px rgba(0,229,255,0.3);
      transform: translateY(-2px);
    }
    .btn-sm {
      padding: 8px 20px;
      font-size: 14px;
    }
    /* 导航 */
    .header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(11, 14, 26, 0.85);
      backdrop-filter: blur(20px);
      border-bottom: 1px solid transparent;
      background-image: linear-gradient(rgba(11,14,26,0.85), rgba(11,14,26,0.85)), linear-gradient(90deg, var(--color-primary), var(--color-secondary));
      background-origin: border-box;
      background-clip: padding-box, border-box;
      border-bottom: 1px solid transparent;
    }
    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .logo {
      font-family: var(--font-heading);
      font-size: 24px;
      font-weight: 700;
      color: white;
      display: flex;
      align-items: baseline;
      gap: 8px;
    }
    .logo span {
      color: var(--color-secondary);
    }
    .logo small {
      font-size: 12px;
      color: var(--color-text-soft);
      font-weight: 400;
      font-family: var(--font-body);
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .nav-links a {
      font-size: 15px;
      font-weight: 500;
      color: var(--color-text-muted);
      position: relative;
      padding: 4px 0;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 50%;
      width: 0;
      height: 2px;
      background: var(--color-secondary);
      transition: all 0.3s ease;
      transform: translateX(-50%);
    }
    .nav-links a:hover {
      color: var(--color-secondary);
    }
    .nav-links a:hover::after {
      width: 100%;
    }
    .hamburger {
      display: none;
      background: none;
      border: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--color-secondary);
      display: block;
      transition: 0.3s;
      border-radius: 2px;
    }
    @media (max-width: 768px) {
      .nav-links {
        display: none;
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        background: rgba(11,14,26,0.95);
        backdrop-filter: blur(24px);
        flex-direction: column;
        padding: 32px;
        gap: 24px;
        border-bottom: 1px solid rgba(108,60,240,0.4);
      }
      .nav-links.active {
        display: flex;
      }
      .hamburger {
        display: flex;
      }
    }
    /* 板块通用 */
    section {
      padding: 100px 0;
      scroll-margin-top: 80px;
    }
    @media (max-width: 768px) {
      section {
        padding: 60px 0;
      }
    }
    .section-title {
      font-size: 36px;
      font-weight: 600;
      color: white;
      margin-bottom: 16px;
      line-height: 1.3;
    }
    @media (max-width: 768px) {
      .section-title {
        font-size: 28px;
      }
    }
    /* 卡片通用 */
    .card {
      background: var(--color-surface);
      backdrop-filter: blur(12px);
      border: 1px solid rgba(108,60,240,0.2);
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow-card);
      transition: all 0.3s ease;
    }
    .card:hover {
      transform: translateY(-6px);
      border-color: rgba(108,60,240,0.6);
      box-shadow: 0 16px 40px rgba(0,0,0,0.5), 0 0 12px rgba(108,60,240,0.4);
    }
    /* hero */
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }
    .hero h1 {
      font-size: 48px;
      font-weight: 700;
      color: white;
      line-height: 1.2;
      margin-bottom: 20px;
    }
    .hero .highlight {
      color: var(--color-secondary);
    }
    .hero p {
      font-size: 18px;
      color: var(--color-text-muted);
      margin-bottom: 32px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
      margin-bottom: 40px;
    }
    .hero-stats {
      display: flex;
      gap: 32px;
    }
    .stat-item {
      text-align: left;
    }
    .stat-number {
      font-size: 28px;
      font-weight: 700;
      color: var(--color-secondary);
    }
    .hero-image {
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: 24px;
      height: 400px;
      position: relative;
      overflow: hidden;
      box-shadow: 0 20px 40px rgba(0,229,255,0.15);
    }
    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 40px;
      }
      .hero h1 {
        font-size: 32px;
      }
    }
    /* about 非对称 */
    .about-grid {
      display: grid;
      grid-template-columns: 5fr 7fr;
      gap: 24px;
    }
    .about-left {
      background: url('/assets/images/coverpic/cover-1.webp') center/cover no-repeat;
      border-radius: var(--radius-card);
      min-height: 320px;
      position: relative;
    }
    .about-right {
      display: grid;
      grid-template-rows: 1fr 1fr;
      gap: 24px;
    }
    @media (max-width: 768px) {
      .about-grid {
        grid-template-columns: 1fr;
      }
      .about-left {
        min-height: 240px;
      }
    }
    /* services */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .service-card img {
      border-radius: 12px;
      height: 180px;
      object-fit: cover;
      margin-bottom: 16px;
    }
    @media (max-width: 768px) {
      .services-grid {
        grid-template-columns: 1fr;
      }
    }
    /* data */
    .data-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
      text-align: center;
    }
    .data-number {
      font-size: 56px;
      font-weight: 700;
      color: var(--color-secondary);
      line-height: 1.1;
    }
    @media (max-width: 768px) {
      .data-grid {
        grid-template-columns: 1fr 1fr;
      }
    }
    /* cases 横向滚动 */
    .cases-scroll {
      display: flex;
      gap: 24px;
      overflow-x: auto;
      padding-bottom: 16px;
      scroll-snap-type: x mandatory;
    }
    .case-card {
      flex: 0 0 320px;
      scroll-snap-align: start;
      border-radius: var(--radius-card);
      background-size: cover;
      background-position: center;
      height: 280px;
      position: relative;
      overflow: hidden;
    }
    .case-info {
      position: absolute;
      bottom: 0;
      left: 0;
      right: 0;
      padding: 24px;
      background: linear-gradient(transparent, rgba(11,14,26,0.9));
      color: white;
    }
    .case-card:nth-child(1) { background-image: url('/assets/images/backpic/back-2.webp'); }
    .case-card:nth-child(2) { background-image: url('/assets/images/backpic/back-3.webp'); }
    .case-card:nth-child(3) { background-image: url('/assets/images/coverpic/cover-2.webp'); }
    .case-card:nth-child(4) { background-image: url('/assets/images/coverpic/cover-3.webp'); }

    /* faq */
    .faq-item {
      border-bottom: 1px solid rgba(108,60,240,0.25);
      padding: 20px 0;
      cursor: pointer;
    }
    .faq-question {
      font-weight: 600;
      font-size: 18px;
      color: white;
      display: flex;
      justify-content: space-between;
    }
    .faq-answer {
      margin-top: 12px;
      color: var(--color-text-muted);
      display: none;
    }
    .faq-item.active .faq-answer {
      display: block;
    }
    /* cta */
    .cta-section {
      background: #0B0E1A;
    }
    /* footer */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }