/* roulang page: index */
:root {
      --primary: #7B2FF7;
      --secondary: #00F0B5;
      --accent: #FF6B35;
      --bg-deep: #0F0A1A;
      --bg-card: #1A1326;
      --text-main: #FFFFFF;
      --text-muted: #B0AACC;
      --border-glow: rgba(123,47,247,0.25);
      --radius-lg: 16px;
      --radius-md: 12px;
      --shadow-glow: 0 12px 24px rgba(123,47,247,0.3);
      --transition: 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    }

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

    body {
      font-family: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      background-color: var(--bg-deep);
      color: var(--text-main);
      line-height: 1.8;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 导航桌面固定 */
    .main-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(15, 10, 26, 0.88);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      z-index: 100;
      height: 72px;
      border-bottom: 1px solid rgba(123,47,247,0.18);
    }

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

    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 800;
      font-size: 1.6rem;
      color: white;
      letter-spacing: 1px;
      text-decoration: none;
    }
    .logo i {
      color: var(--secondary);
      font-size: 2rem;
    }

    .nav-links {
      display: flex;
      gap: 2.5rem;
      align-items: center;
    }

    .nav-links a {
      color: var(--text-muted);
      text-decoration: none;
      font-weight: 500;
      position: relative;
      padding: 8px 0;
      transition: color 0.2s;
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--secondary);
      transition: width var(--transition);
    }

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

    .nav-links a:hover::after {
      width: 100%;
    }

    .hamburger {
      display: none;
      background: none;
      border: none;
      color: white;
      font-size: 1.8rem;
      cursor: pointer;
    }

    /* 移动底部导航 */
    .mobile-bottom-nav {
      display: none;
      position: fixed;
      bottom: 0;
      left: 0;
      width: 100%;
      background: rgba(15, 10, 26, 0.95);
      backdrop-filter: blur(15px);
      border-top: 1px solid rgba(123,47,247,0.25);
      justify-content: space-around;
      align-items: center;
      height: 64px;
      z-index: 100;
    }

    .mobile-bottom-nav a {
      color: var(--text-muted);
      text-decoration: none;
      display: flex;
      flex-direction: column;
      align-items: center;
      font-size: 0.7rem;
      gap: 4px;
      transition: color 0.2s;
    }

    .mobile-bottom-nav a i {
      font-size: 1.4rem;
    }

    .mobile-bottom-nav a.active, .mobile-bottom-nav a:hover {
      color: var(--secondary);
    }

    /* 按钮系统 */
    .btn-primary {
      background: var(--primary);
      color: white;
      border: none;
      padding: 14px 32px;
      border-radius: var(--radius-md);
      font-weight: 600;
      cursor: pointer;
      transition: background 0.2s, box-shadow 0.2s, color 0.2s;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      text-decoration: none;
    }

    .btn-primary:hover {
      background: var(--secondary);
      color: #0F0A1A;
      box-shadow: 0 0 20px rgba(0,240,181,0.5);
    }

    .btn-outline {
      background: transparent;
      border: 2px solid var(--secondary);
      color: var(--secondary);
      padding: 12px 30px;
      border-radius: var(--radius-md);
      font-weight: 600;
      cursor: pointer;
      transition: all 0.25s;
      text-decoration: none;
    }

    .btn-outline:hover {
      background: var(--secondary);
      color: #0F0A1A;
    }

    /* 卡片 */
    .card {
      background: var(--bg-card);
      border-radius: var(--radius-lg);
      padding: 28px 24px;
      border: 1px solid var(--border-glow);
      transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
    }

    .card:hover {
      transform: translateY(-6px);
      border-color: var(--secondary);
      box-shadow: var(--shadow-glow);
    }

    h1 {
      font-size: 3rem;
      font-weight: 800;
      line-height: 1.2;
      letter-spacing: -0.5px;
    }

    h2 {
      font-size: 2.25rem;
      font-weight: 700;
      margin-bottom: 1.5rem;
    }

    h3 {
      font-size: 1.5rem;
      font-weight: 600;
    }

    .text-muted {
      color: var(--text-muted);
    }

    /* FAQ 手风琴 */
    .faq-item {
      background: var(--bg-card);
      border-left: 3px solid var(--secondary);
      border-radius: 0 12px 12px 0;
      margin-bottom: 12px;
      transition: all 0.2s;
    }
    .faq-question {
      padding: 18px 24px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: white;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-muted);
      padding: 0 24px;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }
    .faq-item i {
      transition: transform 0.3s;
      color: var(--secondary);
    }
    .faq-item.open i {
      transform: rotate(45deg);
    }

    @media (max-width: 1024px) {
      h1 { font-size: 2.4rem; }
      h2 { font-size: 1.9rem; }
      .nav-links { display: none; }
      .hamburger { display: block; }
    }

    @media (max-width: 768px) {
      .container { padding: 0 20px; }
      h1 { font-size: 2rem; }
      h2 { font-size: 1.7rem; }
      .mobile-bottom-nav { display: flex; }
      .main-header .nav-links { display: none; }
      .hero-grid { flex-direction: column; }
      .service-grid { grid-template-columns: 1fr; }
    }