/* roulang page: index */
:root {
      --primary: #7B2FBE;
      --primary-light: #9b4fdf;
      --accent: #00F0A8;
      --accent-hover: #00d896;
      --dark-bg: #0D0D12;
      --light-bg: #F8F9FC;
      --text-dark: #1A1A2E;
      --text-muted: #6B7280;
      --white: #FFFFFF;
      --card-shadow: 0 8px 24px rgba(123, 47, 190, 0.08);
      --card-shadow-hover: 0 16px 40px rgba(123, 47, 190, 0.15);
      --radius-sm: 8px;
      --radius: 12px;
      --radius-lg: 16px;
      --transition: 0.25s ease;
      --nav-height: 72px;
      --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
      scroll-padding-top: var(--nav-height);
    }
    body {
      font-family: var(--font-sans);
      font-size: 16px;
      line-height: 1.8;
      background-color: var(--white);
      color: var(--text-dark);
      -webkit-font-smoothing: antialiased;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }
    img {
      max-width: 100%;
      display: block;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      border: none;
      font-weight: 600;
      letter-spacing: 0.3px;
      transition: var(--transition);
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 28px;
      width: 100%;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 20px;
      }
    }
    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background: var(--white);
      box-shadow: 0 1px 0 rgba(0,0,0,0.05);
      z-index: 1000;
      display: flex;
      align-items: center;
    }
    .header-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo {
      font-weight: 700;
      font-size: 24px;
      color: var(--primary);
      display: flex;
      align-items: center;
      gap: 8px;
      letter-spacing: -0.3px;
    }
    .logo svg {
      width: 28px;
      height: 28px;
      fill: var(--accent);
      flex-shrink: 0;
    }
    .nav-menu {
      display: flex;
      gap: 32px;
      list-style: none;
    }
    .nav-menu a {
      font-size: 15px;
      font-weight: 500;
      color: var(--text-dark);
      position: relative;
      padding: 4px 0;
    }
    .nav-menu a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent);
      transition: width 0.2s;
      border-radius: 2px;
    }
    .nav-menu a:hover {
      color: var(--primary);
    }
    .nav-menu a:hover::after {
      width: 100%;
    }
    .hamburger {
      display: none;
      background: none;
      border: none;
      flex-direction: column;
      gap: 5px;
      width: 28px;
    }
    .hamburger span {
      display: block;
      height: 2px;
      background: var(--text-dark);
      border-radius: 2px;
      transition: 0.2s;
    }
    @media (max-width: 1024px) {
      .nav-menu {
        gap: 20px;
      }
    }
    @media (max-width: 768px) {
      .hamburger {
        display: flex;
      }
      .nav-menu {
        position: fixed;
        top: var(--nav-height);
        left: 0;
        width: 100%;
        height: 0;
        overflow: hidden;
        background: rgba(13, 13, 18, 0.96);
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 28px;
        transition: height 0.3s ease;
        backdrop-filter: blur(8px);
      }
      .nav-menu.active {
        height: calc(100vh - var(--nav-height));
      }
      .nav-menu a {
        color: var(--white);
        font-size: 20px;
      }
    }
    /* Hero */
    .hero {
      background-color: var(--dark-bg);
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      position: relative;
      padding: 140px 0 100px;
      display: flex;
      align-items: center;
    }
    .hero::after {
      content: '';
      position: absolute;
      inset: 0;
      background: radial-gradient(circle at 30% 40%, rgba(123,47,190,0.35) 0%, rgba(13,13,18,0.85) 70%);
      z-index: 1;
    }
    .hero-content {
      position: relative;
      z-index: 2;
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-text {
      flex: 1;
    }
    .hero h1 {
      font-size: 48px;
      font-weight: 700;
      letter-spacing: -0.5px;
      color: #FFFFFF;
      line-height: 1.25;
      margin-bottom: 20px;
    }
    .hero-sub {
      font-size: 18px;
      color: #B0B0C0;
      margin-bottom: 36px;
      max-width: 560px;
    }
    .btn-group {
      display: flex;
      flex-wrap: wrap;
      gap: 16px;
    }
    .btn-primary {
      background: var(--accent);
      color: #0D0D12;
      font-size: 17px;
      padding: 14px 32px;
      border-radius: var(--radius-sm);
      font-weight: 700;
    }
    .btn-primary:hover {
      background: var(--accent-hover);
      filter: brightness(1.08);
    }
    .btn-outline {
      border: 1px solid rgba(255,255,255,0.5);
      background: transparent;
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-sm);
      font-weight: 600;
    }
    .btn-outline:hover {
      background: white;
      color: var(--primary);
      border-color: white;
    }
    .hero-visual {
      flex: 0 0 420px;
      background: rgba(123,47,190,0.2);
      border-radius: var(--radius-lg);
      overflow: hidden;
      box-shadow: 0 20px 40px rgba(0,0,0,0.5);
      backdrop-filter: blur(4px);
    }
    @media (max-width: 1024px) {
      .hero-content {
        flex-direction: column;
        text-align: center;
      }
      .hero-visual {
        width: 100%;
        max-width: 480px;
      }
      .btn-group {
        justify-content: center;
      }
    }
    /* sections */
    section {
      padding: 80px 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 56px;
    }
    .section-title h2 {
      font-size: 36px;
      font-weight: 700;
      color: var(--text-dark);
    }
    .bg-light {
      background: var(--light-bg);
    }
    .bg-dark {
      background: var(--dark-bg);
      color: white;
    }
    .cards-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 28px;
    }
    @media (max-width: 1024px) {
      .cards-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 640px) {
      .cards-grid {
        grid-template-columns: 1fr;
      }
    }
    .adv-card {
      background: var(--white);
      padding: 28px 24px;
      border-radius: var(--radius-lg);
      box-shadow: var(--card-shadow);
      transition: all 0.25s;
    }
    .adv-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--card-shadow-hover);
    }
    .icon-circle {
      width: 64px;
      height: 64px;
      background: rgba(123,47,190,0.08);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
    }
    .icon-circle svg {
      width: 32px;
      height: 32px;
      fill: var(--accent);
    }
    .service-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }
    @media (max-width: 768px) {
      .service-grid {
        grid-template-columns: 1fr;
      }
    }
    .service-card {
      background: var(--white);
      border-radius: var(--radius-lg);
      overflow: hidden;
      box-shadow: var(--card-shadow);
      transition: var(--transition);
    }
    .service-card:hover {
      transform: translateY(-5px);
      box-shadow: var(--card-shadow-hover);
    }
    .service-img {
      height: 200px;
      background-size: cover;
      background-position: center;
    }
    .service-body {
      padding: 24px 24px 20px;
    }
    .stats-row {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      text-align: center;
      gap: 20px;
    }
    @media (max-width: 640px) {
      .stats-row {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    .stat-number {
      font-size: 56px;
      font-weight: 800;
      color: var(--accent);
    }
    .case-item {
      display: flex;
      gap: 40px;
      margin-bottom: 48px;
      align-items: center;
    }
    @media (max-width: 768px) {
      .case-item {
        flex-direction: column;
      }
    }
    .case-img {
      flex: 0 0 400px;
      height: 280px;
      border-radius: var(--radius);
      background-size: cover;
    }
    .steps {
      display: flex;
      justify-content: space-between;
      text-align: center;
    }
    @media (max-width: 768px) {
      .steps {
        flex-direction: column;
        gap: 30px;
      }
    }
    .faq-item {
      background: var(--white);
      border-radius: var(--radius);
      margin-bottom: 12px;
      overflow: hidden;
    }
    .faq-question {
      padding: 20px 24px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      color: var(--primary);
    }
    .faq-answer {
      padding: 0 24px 20px;
      color: var(--text-muted);
      display: none;
    }
    .faq-item.active .faq-answer {
      display: block;
    }
    .footer {
      background: var(--light-bg);
    }
    .copyright {
      background: var(--dark-bg);
      color: #aaa;
      text-align: center;
      padding: 18px 0;
    }