/* roulang page: index */
/* ----- 设计变量与基础重置 ----- */
    :root {
      --bg-deep: #0A0A0C;
      --bg-card: #12141D;
      --violet-electric: #B44CFF;
      --cyan-aurora: #00F0FF;
      --amber-warning: #FF8A00;
      --text-primary: #E0E5EC;
      --text-secondary: #A0A8B8;
      --border-dim: #2A2D3A;
      --radius-sm: 6px;
      --shadow-card: 0 8px 24px rgba(0,0,0,0.6);
      --glow-violet: 0 0 12px rgba(180,76,255,0.5);
      --glow-cyan: 0 0 10px rgba(0,240,255,0.45);
      --transition-smooth: all 0.25s ease;
    }

    * {
      box-sizing: border-box;
    }

    body {
      background-color: var(--bg-deep);
      color: var(--text-secondary);
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
      line-height: 1.7;
      margin: 0;
      padding: 0;
      font-weight: 400;
      font-size: 1rem;
      -webkit-font-smoothing: antialiased;
    }

    h1, h2, h3, h4 {
      color: var(--text-primary);
      font-weight: 600;
      letter-spacing: -0.01em;
    }

    h1 {
      font-weight: 700;
      font-size: clamp(2.8rem, 8vw, 4.8rem);
      letter-spacing: -0.02em;
      line-height: 1.1;
    }

    h2 {
      font-size: clamp(2rem, 6vw, 3rem);
      margin-bottom: 1.5rem;
      position: relative;
      display: inline-block;
    }

    .section-title::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: -10px;
      width: 60px;
      height: 3px;
      background: var(--violet-electric);
      box-shadow: var(--glow-violet);
      border-radius: 2px;
    }

    h3 {
      font-size: 1.6rem;
      font-weight: 600;
      margin-bottom: 0.75rem;
    }

    a {
      color: var(--cyan-aurora);
      transition: var(--transition-smooth);
      text-decoration: none;
    }

    a:hover {
      color: var(--violet-electric);
      text-decoration: none;
    }

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

    .container {
      max-width: 1200px;
      margin: 0 auto;
    }

    /* 导航栏 */
    .nav-container {
      background: rgba(10, 10, 12, 0.88);
      backdrop-filter: blur(18px);
      -webkit-backdrop-filter: blur(18px);
      border-bottom: 1px solid var(--violet-electric);
      box-shadow: 0 2px 18px rgba(180,76,255,0.2);
      position: sticky;
      top: 0;
      z-index: 50;
      padding: 0.75rem 0;
    }

    .nav-logo {
      font-weight: 700;
      font-size: 1.7rem;
      color: #fff;
      letter-spacing: 0.5px;
      background: linear-gradient(135deg, #fff 0%, var(--violet-electric) 90%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }

    .nav-link {
      color: var(--text-secondary);
      font-weight: 500;
      padding: 0.5rem 1rem;
      transition: var(--transition-smooth);
      font-size: 0.95rem;
      border-bottom: 2px solid transparent;
    }

    .nav-link:hover {
      color: #fff;
    }

    .nav-link.active {
      color: var(--violet-electric);
      border-bottom-color: var(--violet-electric);
      box-shadow: 0 4px 8px rgba(180,76,255,0.3);
    }

    .btn-nav-cta {
      background: var(--violet-electric);
      color: #fff;
      font-weight: 600;
      letter-spacing: 0.05em;
      text-transform: uppercase;
      padding: 0.6rem 1.5rem;
      border-radius: var(--radius-sm);
      transition: var(--transition-smooth);
      border: none;
      font-size: 0.9rem;
    }

    .btn-nav-cta:hover {
      background: var(--amber-warning);
      color: #000;
      box-shadow: 0 0 18px var(--amber-warning);
      transform: scale(1.03);
    }

    /* 汉堡菜单定制 */
    .menu-icon.dark::after {
      background: #fff;
      box-shadow: 0 7px 0 #fff, 0 14px 0 #fff;
    }

    /* Hero */
    .hero-section {
      min-height: 92vh;
      display: flex;
      align-items: center;
      background: radial-gradient(circle at 30% 40%, #1a1025 0%, #0A0A0C 80%);
      position: relative;
      overflow: hidden;
      border-bottom: 1px solid rgba(180,76,255,0.25);
    }

    .hero-bg-img {
      position: absolute;
      inset: 0;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      opacity: 0.18;
      z-index: 0;
      filter: blur(1px) brightness(0.7);
    }

    .hero-content {
      position: relative;
      z-index: 2;
    }

    .btn-primary {
      background: var(--violet-electric);
      color: #fff;
      font-weight: 600;
      letter-spacing: 0.06em;
      text-transform: uppercase;
      padding: 0.9rem 2.5rem;
      border-radius: var(--radius-sm);
      border: none;
      transition: 0.3s;
      font-size: 1rem;
      box-shadow: 0 0 20px rgba(180,76,255,0.6);
    }

    .btn-primary:hover {
      background: var(--amber-warning);
      color: #0A0A0C;
      box-shadow: 0 0 28px var(--amber-warning);
      transform: translateY(-3px);
    }

    .btn-outline-light {
      border: 1px solid var(--text-primary);
      color: var(--text-primary);
      padding: 0.7rem 2rem;
      border-radius: var(--radius-sm);
      font-weight: 500;
      transition: var(--transition-smooth);
    }

    .btn-outline-light:hover {
      border-color: var(--violet-electric);
      background: rgba(180,76,255,0.1);
    }

    /* 卡片通用 */
    .feature-card, .case-card {
      background: var(--bg-card);
      border-radius: var(--radius-sm);
      padding: 2rem;
      border: 1px solid transparent;
      transition: var(--transition-smooth);
      box-shadow: 0 6px 18px rgba(0,0,0,0.55);
    }

    .feature-card:hover, .case-card:hover {
      border-color: var(--violet-electric);
      box-shadow: 0 0 25px rgba(180,76,255,0.5);
      transform: translateY(-8px);
      background: #1a1c26;
    }

    .icon-glow {
      color: var(--cyan-aurora);
      font-size: 2.4rem;
      margin-bottom: 1.2rem;
      filter: drop-shadow(0 0 8px var(--cyan-aurora));
    }

    .stat-highlight {
      color: var(--cyan-aurora);
      font-weight: 700;
      font-size: 2.2rem;
    }

    /* 交替图文 */
    .alt-image-block img {
      border-radius: var(--radius-sm);
      box-shadow: 0 0 30px rgba(180,76,255,0.3);
      border: 1px solid rgba(180,76,255,0.4);
    }

    /* FAQ 手风琴 */
    .accordion-item {
      background: var(--bg-card);
      border-bottom: 1px solid var(--border-dim);
      border-radius: 0;
    }

    .accordion-title {
      background: transparent;
      color: var(--text-primary);
      font-weight: 600;
      font-size: 1.15rem;
      padding: 1.25rem;
      border: none;
      transition: var(--transition-smooth);
    }

    .accordion-title:hover {
      background: #1e1f2b;
    }

    .accordion-content {
      background: #0f1016;
      color: var(--text-secondary);
      padding: 0 1.25rem 1.25rem;
    }

    /* 页脚 */
    .site-footer {
      background: #050508;
      border-top: 1px solid var(--violet-electric);
      padding: 3rem 1rem;
    }

    .footer-logo {
      font-weight: 700;
      font-size: 1.8rem;
      background: linear-gradient(135deg, #E0E5EC, var(--violet-electric));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    @media (max-width: 640px) {
      .hero-section {
        min-height: 85vh;
      }
      .alt-image-block {
        flex-direction: column;
      }
    }