/* roulang page: index */
:root {
      --color-deep: #0B0C10;
      --color-slate: #161B22;
      --color-accent: #E2E8F0;
      --color-muted: #94A3B8;
      --color-border: rgba(255,255,255,0.08);
      --color-glow: rgba(226,232,240,0.15);
      --font-sans: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
    }
    * {
      box-sizing: border-box;
    }
    body {
      margin: 0;
      font-family: var(--font-sans);
      background-color: var(--color-deep);
      color: #ffffff;
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
    }
    .container-custom {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }
    @media (min-width: 768px) {
      .container-custom {
        padding-left: 2.5rem;
        padding-right: 2.5rem;
      }
    }
    /* 导航与滚动偏移 */
    html {
      scroll-behavior: smooth;
    }
    .nav-blur {
      background-color: rgba(11,12,16,0.8);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
    }
    .nav-link {
      color: #C0C4CC;
      transition: color 0.2s, border-color 0.2s;
      border-bottom: 2px solid transparent;
      padding-bottom: 4px;
    }
    .nav-link:hover {
      color: #ffffff;
    }
    .active-nav {
      color: #ffffff;
      border-bottom-color: var(--color-accent);
    }
    /* 按钮体系 */
    .btn-primary {
      background-color: var(--color-accent);
      color: #0B0C10;
      font-weight: 500;
      letter-spacing: 0.5px;
      border-radius: 6px;
      padding: 0.75rem 1.8rem;
      transition: all 0.25s ease;
      box-shadow: 0 4px 12px rgba(226,232,240,0.15);
      border: 1px solid transparent;
      display: inline-block;
      text-align: center;
    }
    .btn-primary:hover {
      background-color: #ffffff;
      box-shadow: 0 8px 18px rgba(226,232,240,0.3);
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      border: 1px solid var(--color-accent);
      color: var(--color-accent);
      font-weight: 500;
      letter-spacing: 0.5px;
      border-radius: 6px;
      padding: 0.75rem 1.8rem;
      transition: all 0.25s ease;
      display: inline-block;
      text-align: center;
    }
    .btn-outline:hover {
      background-color: rgba(226,232,240,0.08);
      border-color: #ffffff;
      color: #ffffff;
    }
    /* 卡片样式 */
    .card-dark {
      background: rgba(255,255,255,0.03);
      border: 1px solid rgba(255,255,255,0.06);
      border-radius: 10px;
      padding: 2rem;
      transition: all 0.3s ease;
    }
    .card-dark:hover {
      border-color: rgba(226,232,240,0.25);
      transform: translateY(-4px);
      background: rgba(255,255,255,0.05);
    }
    .service-card-special {
      background: rgba(255,255,255,0.04);
      border: 1px solid rgba(226,232,240,0.18);
      box-shadow: 0 0 15px rgba(226,232,240,0.03);
    }
    .case-img-wrapper {
      position: relative;
      overflow: hidden;
      border-radius: 8px;
      border: 1px solid rgba(255,255,255,0.1);
      background-color: #0B0C10;
      aspect-ratio: 16 / 9;
    }
    .case-img-wrapper img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: transform 0.4s ease;
      filter: brightness(0.7);
    }
    .card-dark:hover .case-img-wrapper img {
      transform: scale(1.03);
      filter: brightness(0.85);
    }
    /* 流程线 */
    .process-line {
      height: 1px;
      background: rgba(255,255,255,0.1);
      flex: 1;
      margin: 0 8px;
    }
    .faq-question {
      cursor: pointer;
      transition: color 0.2s;
    }
    .faq-question:hover {
      color: var(--color-accent);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.25s ease;
      color: #94A3B8;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-top: 1rem;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    .faq-icon {
      transition: transform 0.25s ease;
      color: #94A3B8;
    }
    /* 汉堡菜单动画 */
    .mobile-menu {
      transition: opacity 0.3s ease, transform 0.3s ease;
      transform: translateY(-10px);
      opacity: 0;
      pointer-events: none;
    }
    .mobile-menu.open {
      transform: translateY(0);
      opacity: 1;
      pointer-events: auto;
    }
    /* 背景星点装饰 */
    .hero-bg-glow {
      position: absolute;
      top: 20%;
      left: 50%;
      width: 600px;
      height: 600px;
      background: radial-gradient(circle, rgba(226,232,240,0.08) 0%, transparent 70%);
      transform: translate(-50%, -50%);
      pointer-events: none;
    }
    @media (max-width: 768px) {
      .hero-bg-glow {
        width: 300px;
        height: 300px;
      }
    }