/* roulang page: index */
:root {
      --deep-purple: #4A1D6B;
      --electric-cyan: #00E5FF;
      --warm-white: #F7F5F9;
      --pure-white: #FFFFFF;
      --charcoal: #1E1E2F;
      --slate: #6B6B7B;
      --border-light: rgba(74, 29, 107, 0.08);
      --shadow-card: 0 4px 20px rgba(74, 29, 107, 0.06);
      --shadow-hover: 0 8px 30px rgba(74, 29, 107, 0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --transition: 0.25s ease;
      --max-width: 1200px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      background-color: var(--warm-white);
      color: var(--charcoal);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    img {
      max-width: 100%;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
    }

    /* Header & Navigation */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: var(--pure-white);
      border-bottom: 1px solid var(--border-light);
      z-index: 1000;
      display: flex;
      align-items: center;
    }
    .header-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--deep-purple);
      display: flex;
      align-items: center;
      gap: 6px;
      letter-spacing: 1px;
    }
    .logo-icon {
      font-size: 28px;
      color: var(--electric-cyan);
    }
    .nav-menu {
      display: flex;
      gap: 32px;
      list-style: none;
      align-items: center;
    }
    .nav-menu a {
      font-size: 16px;
      font-weight: 500;
      color: var(--charcoal);
      padding: 8px 0;
      position: relative;
      transition: color 0.2s;
    }
    .nav-menu a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--electric-cyan);
      transition: width 0.25s ease;
    }
    .nav-menu a:hover,
    .nav-menu a.active {
      color: var(--electric-cyan);
    }
    .nav-menu a:hover::after,
    .nav-menu a.active::after {
      width: 100%;
    }
    .btn-primary {
      background: var(--deep-purple);
      color: white;
      font-weight: 600;
      font-size: 16px;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      border: none;
      transition: background 0.25s, box-shadow 0.25s;
      display: inline-block;
    }
    .btn-primary:hover {
      background: #5E2A80;
      box-shadow: 0 0 16px rgba(74, 29, 107, 0.3);
    }
    .btn-secondary {
      background: transparent;
      border: 2px solid var(--deep-purple);
      color: var(--deep-purple);
      font-weight: 600;
      font-size: 16px;
      padding: 12px 32px;
      border-radius: var(--radius-btn);
      transition: all 0.25s;
      display: inline-block;
    }
    .btn-secondary:hover {
      background: var(--deep-purple);
      color: white;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
    }
    .hamburger span {
      width: 25px;
      height: 3px;
      background: var(--deep-purple);
      border-radius: 3px;
      transition: 0.3s;
    }

    @media (max-width: 768px) {
      .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        width: 100%;
        height: 0;
        overflow: hidden;
        flex-direction: column;
        background: var(--pure-white);
        gap: 28px;
        padding: 0 24px;
        transition: height 0.4s ease, padding 0.4s;
        box-shadow: 0 10px 20px rgba(0,0,0,0.05);
      }
      .nav-menu.active {
        height: calc(100vh - 72px);
        padding: 32px 24px;
        justify-content: center;
      }
      .hamburger {
        display: flex;
      }
      .header-container .btn-primary {
        display: none;
      }
    }

    /* Hero */
    .hero {
      padding: 140px 0 100px;
      display: flex;
      align-items: center;
      gap: 60px;
      flex-wrap: wrap;
    }
    .hero-left {
      flex: 1 1 55%;
    }
    .hero-right {
      flex: 1 1 40%;
    }
    .hero h1 {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--deep-purple);
      margin-bottom: 20px;
    }
    .hero-sub {
      font-size: 18px;
      color: var(--slate);
      margin-bottom: 36px;
      line-height: 1.6;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image {
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: 16px;
      min-height: 380px;
      box-shadow: 0 20px 35px rgba(74,29,107,0.18);
      transform: perspective(800px) rotateY(-3deg);
    }

    /* Sections */
    section {
      padding: 70px 0;
    }
    .section-title {
      font-size: 36px;
      font-weight: 700;
      color: var(--charcoal);
      margin-bottom: 20px;
      text-align: center;
    }
    .section-desc {
      text-align: center;
      color: var(--slate);
      max-width: 680px;
      margin: 0 auto 50px;
    }

    /* Advantages - asymmetric */
    .adv-grid {
      display: grid;
      grid-template-columns: 1fr 1fr 1.3fr;
      gap: 24px;
    }
    .adv-left-stack {
      display: flex;
      flex-direction: column;
      gap: 24px;
    }
    .adv-card {
      background: var(--pure-white);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .adv-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }
    .adv-icon {
      width: 48px;
      height: 48px;
      background: rgba(0, 229, 255, 0.1);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--electric-cyan);
      font-size: 24px;
      margin-bottom: 20px;
    }
    .adv-card h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 12px;
    }
    .adv-card p {
      color: var(--slate);
      font-size: 15px;
    }

    /* Services - image + text alternating */
    .service-row {
      display: flex;
      gap: 40px;
      align-items: center;
      margin-bottom: 60px;
    }
    .service-row.reverse {
      flex-direction: row-reverse;
    }
    .service-img {
      flex: 1;
      background: url('/assets/images/coverpic/cover-2.webp') center/cover no-repeat;
      min-height: 360px;
      border-radius: var(--radius-card);
    }
    .service-text {
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 28px;
    }
    .service-item {
      cursor: pointer;
      transition: transform 0.2s;
    }
    .service-item:hover {
      transform: translateX(4px);
      color: var(--electric-cyan);
    }
    .service-num {
      font-size: 40px;
      font-weight: 800;
      color: rgba(74, 29, 107, 0.1);
      margin-bottom: 6px;
    }

    /* Stats */
    .stats-grid {
      display: flex;
      justify-content: space-around;
      text-align: center;
      gap: 20px;
      flex-wrap: wrap;
    }
    .stat-number {
      font-size: 56px;
      font-weight: 800;
      color: var(--deep-purple);
    }

    /* Cases */
    .cases-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 30px;
    }
    .case-card {
      background: var(--pure-white);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .case-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .case-img {
      height: 220px;
      background-size: cover;
      background-position: center;
    }
    .case-content {
      padding: 24px;
    }

    /* FAQ */
    .faq-item {
      background: var(--pure-white);
      border-radius: var(--radius-card);
      margin-bottom: 12px;
      border: 1px solid transparent;
      transition: 0.3s;
    }
    .faq-question {
      padding: 20px 24px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      background: #F2F0F5;
      padding: 0 24px;
    }
    .faq-item.active {
      border-color: var(--electric-cyan);
    }

    /* CTA block */
    .cta-block {
      background: linear-gradient(180deg, rgba(74,29,107,0.03) 0%, white 100%);
      text-align: center;
      padding: 80px 24px;
    }

    /* Footer */
    .site-footer {
      background: #2D1145;
      color: #C4B5D4;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 1.5fr 1fr 1fr 1fr;
      gap: 40px;
    }
    @media (max-width: 768px) {
      .hero h1 { font-size: 32px; }
      .adv-grid { grid-template-columns: 1fr; }
      .service-row, .service-row.reverse { flex-direction: column; }
      .cases-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }