/* roulang page: index */
/* ----- 设计变量与基础重置 ----- */
    :root {
      --deep-space: #0D1117;
      --dark-card: #151A25;
      --nebula-purple: #6C3CE1;
      --nebula-hover: #5A2FD0;
      --stellar-silver: #C0C8D8;
      --aurora-cyan: #2EE0C8;
      --glimmer-gold: #F0C060;
      --text-primary: #E0E4EC;
      --text-secondary: rgba(192, 200, 216, 0.7);
      --border-subtle: rgba(192, 200, 216, 0.12);
      --border-active: rgba(108, 60, 225, 0.5);
      --radius-lg: 16px;
      --radius-md: 12px;
      --radius-sm: 8px;
      --shadow-card: 0 4px 24px rgba(0, 0, 0, 0.4);
      --shadow-hover: 0 8px 40px rgba(108, 60, 225, 0.25);
      --transition-base: all 0.3s ease;
      --font-title: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
      --font-body: 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
      --font-number: 'Inter', 'SF Pro Display', system-ui;
    }

    * {
      box-sizing: border-box;
    }

    body {
      background-color: var(--deep-space);
      color: var(--text-primary);
      font-family: var(--font-body);
      font-size: 16px;
      line-height: 1.7;
      margin: 0;
      overflow-x: hidden;
    }

    h1, h2, h3, h4, .navbar-brand, .accordion-button {
      font-family: var(--font-title);
    }

    .number-font {
      font-family: var(--font-number);
    }

    a {
      color: var(--stellar-silver);
      text-decoration: none;
      transition: var(--transition-base);
    }
    a:hover {
      color: var(--aurora-cyan);
    }

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

    .container-custom {
      max-width: 1320px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 20px;
      padding-right: 20px;
    }

    /* 按钮系统 */
    .btn-primary-custom {
      background: var(--nebula-purple);
      color: #fff;
      border: none;
      border-radius: var(--radius-sm);
      padding: 12px 32px;
      font-weight: 600;
      transition: var(--transition-base);
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }
    .btn-primary-custom:hover {
      background: var(--nebula-hover);
      box-shadow: 0 4px 20px rgba(108, 60, 225, 0.5);
      transform: translateY(-2px);
      color: #fff;
    }
    .btn-outline-custom {
      background: transparent;
      border: 1.5px solid var(--stellar-silver);
      color: var(--stellar-silver);
      border-radius: var(--radius-sm);
      padding: 12px 32px;
      font-weight: 600;
      transition: var(--transition-base);
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }
    .btn-outline-custom:hover {
      border-color: var(--aurora-cyan);
      color: var(--aurora-cyan);
      transform: translateY(-2px);
    }
    .btn-sm-custom {
      padding: 8px 20px;
      font-size: 14px;
    }

    /* 玻璃卡片基础 */
    .glass-card {
      background: rgba(21, 26, 37, 0.6);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border: 1px solid var(--border-subtle);
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-card);
      transition: var(--transition-base);
    }
    .glass-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
      border-color: rgba(108, 60, 225, 0.3);
    }

    /* ----- 导航 (透明玻璃沉浸式) ----- */
    #mainNav {
      position: fixed;
      top: 0;
      width: 100%;
      z-index: 1000;
      background: rgba(13, 17, 23, 0.4);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-bottom: 1px solid rgba(192, 200, 216, 0.1);
      transition: var(--transition-base);
    }
    #mainNav.scrolled {
      background: rgba(13, 17, 23, 0.92);
      backdrop-filter: blur(20px);
      box-shadow: 0 2px 20px rgba(0, 0, 0, 0.5);
    }
    .navbar-brand {
      font-size: 24px;
      font-weight: 700;
      color: #fff !important;
      letter-spacing: 2px;
    }
    .nav-link {
      color: var(--stellar-silver) !important;
      font-size: 15px;
      margin: 0 12px;
      transition: var(--transition-base);
    }
    .nav-link:hover, .nav-link.active {
      color: var(--aurora-cyan) !important;
    }
    .navbar-toggler {
      border: none;
      color: var(--stellar-silver);
    }
    .navbar-toggler-icon {
      background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3e%3cpath stroke='rgba(192, 200, 216, 0.8)' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2' d='M4 7h22M4 15h22M4 23h22'/%3e%3c/svg%3e");
    }
    @media (max-width: 991px) {
      .navbar-collapse {
        background: rgba(13, 17, 23, 0.96);
        backdrop-filter: blur(20px);
        padding: 20px;
        border-radius: 0 0 16px 16px;
        margin-top: 10px;
      }
      .nav-link {
        font-size: 18px;
        padding: 12px 0;
      }
    }

    /* Hero 区域 */
    #hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      position: relative;
      color: #fff;
    }
    #hero::before {
      content: '';
      position: absolute;
      top: 0; left: 0; width: 100%; height: 100%;
      background: linear-gradient(135deg, rgba(13,17,23,0.7) 0%, rgba(108,60,225,0.3) 100%);
    }
    .hero-content {
      position: relative;
      z-index: 2;
    }
    .hero-title {
      font-size: clamp(2.5rem, 8vw, 4.5rem);
      font-weight: 700;
      line-height: 1.2;
      background: linear-gradient(135deg, #FFFFFF 0%, #C0C8D8 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .hero-sub {
      font-size: clamp(1.1rem, 3vw, 1.5rem);
      color: rgba(255,255,255,0.7);
      max-width: 700px;
    }

    /* 区块标题 */
    .section-title {
      font-size: 2.25rem;
      font-weight: 700;
      text-align: center;
      margin-bottom: 0.5rem;
    }
    .section-subtitle {
      font-size: 1.1rem;
      color: var(--text-secondary);
      text-align: center;
      margin-bottom: 3rem;
    }

    /* 服务卡片 - 首卡突出 + 瀑布流感 */
    .service-grid {
      display: grid;
      grid-template-columns: 1.5fr 1fr 1fr;
      gap: 24px;
    }
    .service-card {
      background: rgba(21,26,37,0.7);
      backdrop-filter: blur(10px);
      border: 1px solid var(--border-subtle);
      border-radius: var(--radius-lg);
      padding: 28px 24px;
      transition: var(--transition-base);
      display: flex;
      flex-direction: column;
    }
    .service-card:hover {
      transform: translateY(-5px);
      border-color: var(--nebula-purple);
      box-shadow: var(--shadow-hover);
    }
    .service-icon {
      width: 64px;
      height: 64px;
      border-radius: 16px;
      margin-bottom: 20px;
      object-fit: cover;
    }
    .service-title {
      font-size: 1.5rem;
      font-weight: 600;
      margin-bottom: 12px;
    }
    @media (max-width: 992px) {
      .service-grid {
        grid-template-columns: 1fr 1fr;
      }
    }
    @media (max-width: 768px) {
      .service-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 优势数据 */
    .adv-number {
      font-size: 4rem;
      font-weight: 700;
      color: var(--nebula-purple);
      line-height: 1.1;
      font-family: var(--font-number);
    }

    /* 案例卡片 */
    .case-card {
      border-radius: var(--radius-lg);
      overflow: hidden;
      background: #151A25;
      border: 1px solid var(--border-subtle);
      transition: var(--transition-base);
    }
    .case-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .case-img-wrap {
      overflow: hidden;
      position: relative;
    }
    .case-img-wrap img {
      transition: transform 0.5s ease;
      width: 100%;
      height: 220px;
      object-fit: cover;
    }
    .case-card:hover .case-img-wrap img {
      transform: scale(1.05);
    }

    /* FAQ 手风琴 */
    .accordion-button {
      background: transparent !important;
      color: #E0E4EC !important;
      font-weight: 600;
      font-size: 1.1rem;
      border-bottom: 1px solid rgba(192,200,216,0.15);
      box-shadow: none !important;
    }
    .accordion-button:not(.collapsed) {
      border-bottom-color: var(--nebula-purple);
      color: #fff !important;
    }
    .accordion-button:focus {
      box-shadow: 0 0 0 2px rgba(108,60,225,0.4) !important;
    }
    .accordion-button::after {
      background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16' fill='%232EE0C8'%3e%3cpath fill-rule='evenodd' d='M8 4a.5.5 0 0 1 .5.5v3h3a.5.5 0 0 1 0 1h-3v3a.5.5 0 0 1-1 0v-3h-3a.5.5 0 0 1 0-1h3v-3A.5.5 0 0 1 8 4z'/%3e%3c/svg%3e");
    }
    .accordion-button:not(.collapsed)::after {
      background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16' fill='%232EE0C8'%3e%3cpath fill-rule='evenodd' d='M4 8a.5.5 0 0 1 .5-.5h7a.5.5 0 0 1 0 1h-7A.5.5 0 0 1 4 8z'/%3e%3c/svg%3e");
    }

    /* 表单 */
    .form-control-custom {
      background: rgba(255,255,255,0.05);
      border: 1px solid rgba(192,200,216,0.2);
      border-radius: var(--radius-sm);
      color: #fff;
      padding: 14px 16px;
    }
    .form-control-custom:focus {
      border-color: var(--nebula-purple);
      box-shadow: 0 0 0 3px rgba(108,60,225,0.2);
      background: rgba(255,255,255,0.08);
    }

    footer {
      background: #0A0C13;
      border-top: 1px solid rgba(192,200,216,0.1);
    }