/* roulang page: index */
:root {
      --bg-dark: #1a1d23;
      --bg-deep: #15171c;
      --bg-card: #1e2c2a;
      --bg-secondary: #1f2228;
      --primary-orange: #f05a28;
      --accent-gold: #c49a6c;
      --text-primary: #e8e4df;
      --text-secondary: #9b958c;
      --border-dim: #2a2d33;
      --radius-md: 10px;
      --radius-lg: 12px;
      --radius-btn: 8px;
      --shadow-sm: 0 4px 12px rgba(0,0,0,0.25);
      --shadow-hover: 0 12px 28px rgba(0,0,0,0.45);
      --font-mono: 'SF Mono', 'Consolas', 'Monaco', monospace;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', sans-serif;
      --font-title: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --nav-height: 72px;
    }

    * {
      box-sizing: border-box;
    }

    body {
      background-color: var(--bg-dark);
      color: var(--text-primary);
      font-family: var(--font-sans);
      font-size: 15px;
      line-height: 1.7;
      margin: 0;
      overflow-x: hidden;
      -webkit-font-smoothing: antialiased;
    }

    h1, h2, h3, h4 {
      font-family: var(--font-title);
      font-weight: 600;
      letter-spacing: -0.2px;
    }

    a {
      text-decoration: none;
      transition: all 0.25s ease;
    }

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

    .container {
      max-width: 1200px;
      padding-left: 20px;
      padding-right: 20px;
    }

    /* 导航 */
    .navbar {
      height: var(--nav-height);
      background: transparent;
      transition: background 0.3s ease, backdrop-filter 0.3s ease;
      z-index: 1030;
      border-bottom: 1px solid transparent;
      padding: 0;
    }

    .navbar.scrolled {
      background: rgba(26, 29, 35, 0.92);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-dim);
    }

    .navbar-brand {
      font-family: var(--font-mono);
      font-size: 22px;
      font-weight: 700;
      color: var(--primary-orange) !important;
      letter-spacing: 1px;
    }

    .brand-separator {
      color: var(--accent-gold);
      margin: 0 8px;
      font-weight: 300;
    }

    .brand-tag {
      font-size: 12px;
      color: var(--accent-gold);
      font-weight: 500;
      font-family: var(--font-sans);
      letter-spacing: 1px;
    }

    .navbar-nav .nav-link {
      color: var(--text-secondary) !important;
      font-size: 14px;
      font-weight: 500;
      margin: 0 18px;
      padding: 8px 0 !important;
      position: relative;
      transition: color 0.2s;
    }

    .navbar-nav .nav-link:hover {
      color: var(--text-primary) !important;
    }

    .navbar-nav .nav-link.active {
      color: var(--primary-orange) !important;
    }

    .navbar-nav .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 50%;
      transform: translateX(-50%);
      width: 20px;
      height: 2px;
      background: var(--primary-orange);
      border-radius: 2px;
    }

    .btn-nav-cta {
      background: var(--primary-orange);
      color: white;
      font-weight: 600;
      font-size: 14px;
      padding: 10px 22px;
      border-radius: 6px;
      border: none;
      transition: 0.25s;
      white-space: nowrap;
    }

    .btn-nav-cta:hover {
      background: #ff6b3a;
      box-shadow: 0 0 14px rgba(240, 90, 40, 0.5);
      color: white;
    }

    .navbar-toggler {
      border: none;
      color: var(--text-primary);
    }

    .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='%23e8e4df' 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(26, 29, 35, 0.98);
        backdrop-filter: blur(16px);
        padding: 20px;
        border-radius: 0 0 16px 16px;
      }
      .navbar-nav .nav-link {
        margin: 8px 0;
        font-size: 16px;
      }
    }

    /* Hero */
    .hero-section {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: radial-gradient(circle at 30% 50%, rgba(240,90,40,0.08) 0%, transparent 60%),
                  linear-gradient(135deg, #1a1d23 0%, #15171c 100%);
      position: relative;
      overflow: hidden;
    }

    .hero-geo {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background-image: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1200 800" opacity="0.07"><path d="M0 400 L1200 400 M600 0 L600 800" stroke="%23f05a28" stroke-width="1" fill="none"/><circle cx="600" cy="400" r="300" stroke="%23f05a28" stroke-width="1" fill="none"/><circle cx="200" cy="200" r="120" stroke="%23c49a6c" stroke-width="0.5" fill="none"/></svg>');
      background-size: cover;
      pointer-events: none;
    }

    .hero-label {
      font-family: var(--font-mono);
      color: var(--accent-gold);
      font-size: 12px;
      letter-spacing: 2px;
      margin-bottom: 1.2rem;
    }

    .hero-title {
      font-size: 44px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--text-primary);
      margin-bottom: 1.5rem;
    }

    .hero-sub {
      font-size: 18px;
      color: var(--text-secondary);
      max-width: 560px;
      margin-bottom: 2.5rem;
    }

    .btn-primary-lg {
      background: var(--primary-orange);
      border: none;
      color: white;
      font-weight: 600;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-size: 16px;
      transition: all 0.3s;
      box-shadow: 0 4px 12px rgba(240,90,40,0.3);
    }

    .btn-primary-lg:hover {
      background: #ff6e3d;
      transform: translateY(-2px);
      box-shadow: 0 8px 24px rgba(240,90,40,0.6);
      color: white;
    }

    .btn-outline-orange {
      border: 1.5px solid var(--primary-orange);
      color: var(--primary-orange);
      background: transparent;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: 0.3s;
    }

    .btn-outline-orange:hover {
      background: rgba(240,90,40,0.1);
      color: var(--primary-orange);
      border-color: #ff6e3d;
    }

    .hero-visual {
      max-width: 480px;
      opacity: 0.9;
    }

    @media (max-width: 768px) {
      .hero-title {
        font-size: 32px;
      }
      .hero-sub {
        font-size: 16px;
      }
    }

    /* 板块标题 */
    .section-title {
      font-size: 32px;
      font-weight: 600;
      margin-bottom: 1rem;
      color: var(--text-primary);
    }

    .section-divider {
      width: 60px;
      height: 3px;
      background: var(--primary-orange);
      margin: 1rem 0 2.5rem;
    }

    /* 服务卡片 非对称 */
    .service-grid {
      display: grid;
      grid-template-columns: 1.2fr 0.9fr;
      gap: 24px;
    }

    .service-card {
      background: var(--bg-card);
      border-radius: var(--radius-lg);
      padding: 32px;
      transition: all 0.3s;
      border: 1px solid transparent;
    }

    .service-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
      border-color: rgba(240,90,40,0.25);
    }

    .service-icon {
      font-size: 36px;
      color: var(--accent-gold);
      margin-bottom: 16px;
    }

    .service-card h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 12px;
    }

    .service-desc {
      color: var(--text-secondary);
      font-size: 14px;
      margin-bottom: 20px;
    }

    .service-link {
      color: var(--primary-orange);
      font-weight: 600;
      font-size: 13px;
      display: inline-flex;
      align-items: center;
      gap: 6px;
    }

    .service-link i {
      transition: transform 0.2s;
    }

    .service-link:hover i {
      transform: translateX(4px);
    }

    @media (max-width: 992px) {
      .service-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 数据指标 */
    .stats-row {
      display: flex;
      justify-content: space-around;
      text-align: center;
      padding: 2rem 0;
    }

    .stat-item {
      flex: 1;
    }

    .stat-number {
      font-family: var(--font-mono);
      font-size: 48px;
      font-weight: 700;
      color: var(--primary-orange);
    }

    .stat-unit {
      font-size: 24px;
      color: var(--accent-gold);
    }

    .stat-label {
      color: var(--text-secondary);
      font-size: 14px;
      margin-top: 8px;
    }

    .stat-divider {
      width: 1px;
      background: var(--border-dim);
      margin: 0 20px;
    }

    @media (max-width: 768px) {
      .stats-row {
        flex-direction: column;
        gap: 24px;
      }
      .stat-divider {
        width: 60px;
        height: 1px;
        margin: 16px auto;
      }
    }

    /* 案例图文 */
    .case-block {
      display: flex;
      align-items: center;
      gap: 48px;
      margin-bottom: 80px;
    }

    .case-img {
      flex: 1;
      background: var(--bg-card);
      border-radius: var(--radius-md);
      overflow: hidden;
    }

    .case-text {
      flex: 1;
    }

    .case-text h3 {
      font-size: 24px;
      margin-bottom: 1rem;
    }

    .case-list {
      list-style: none;
      padding-left: 0;
    }

    .case-list li {
      padding-left: 20px;
      position: relative;
      margin-bottom: 10px;
      color: var(--text-secondary);
    }

    .case-list li::before {
      content: "●";
      color: var(--accent-gold);
      position: absolute;
      left: 0;
    }

    @media (max-width: 768px) {
      .case-block {
        flex-direction: column;
      }
    }

    /* FAQ */
    .accordion-faq .accordion-item {
      background: var(--bg-secondary);
      border: none;
      border-radius: var(--radius-md);
      margin-bottom: 12px;
    }

    .accordion-button {
      background: transparent;
      color: var(--text-primary);
      font-weight: 600;
      font-size: 16px;
      padding: 20px 28px;
      border-radius: var(--radius-md) !important;
      box-shadow: none;
      border-left: 4px solid var(--primary-orange);
    }

    .accordion-button:not(.collapsed) {
      background: rgba(240,90,40,0.05);
      color: var(--text-primary);
      box-shadow: none;
    }

    .accordion-button::after {
      filter: brightness(0) invert(0.8);
    }

    .accordion-body {
      color: var(--text-secondary);
      padding: 0 28px 20px;
      border-top: 1px solid var(--border-dim);
      margin-top: 8px;
    }

    /* CTA */
    .cta-section {
      background: var(--bg-card);
      padding: 80px 0;
    }

    .form-control {
      background: var(--bg-dark);
      border: 1px solid var(--border-dim);
      color: var(--text-primary);
      border-radius: 6px;
      padding: 12px 16px;
    }

    .form-control:focus {
      border-color: var(--primary-orange);
      box-shadow: 0 0 0 2px rgba(240,90,40,0.2);
    }

    .contact-info i {
      color: var(--accent-gold);
      width: 24px;
    }

    /* Footer */
    .footer {
      background: var(--bg-deep);
      border-top: 1px solid var(--border-dim);
      padding: 60px 0 30px;
    }

    .footer a {
      color: var(--text-secondary);
      font-size: 14px;
    }

    .footer a:hover {
      color: var(--primary-orange);
    }

    .copyright {
      font-size: 12px;
      color: #6b6560;
    }