/* roulang page: index */
:root {
      --bg-deep: #0B0E14;
      --surface: #161A22;
      --gold: #C9A96E;
      --gold-hover: #D4B87A;
      --text-primary: #FFFFFF;
      --text-body: #D1D5DB;
      --text-muted: #9CA3AF;
      --border-subtle: rgba(201,169,110,0.08);
      --border-active: rgba(201,169,110,0.35);
      --radius-card: 12px;
      --radius-btn: 8px;
      --transition-smooth: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
      --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', system-ui, -apple-system, sans-serif;
    }

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

    html {
      scroll-behavior: smooth;
      background-color: var(--bg-deep);
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-deep);
      color: var(--text-body);
      line-height: 1.75;
      font-size: 16px;
      font-weight: 400;
      -webkit-font-smoothing: antialiased;
      padding-bottom: 0;
    }

    @media (max-width: 768px) {
      body {
        padding-bottom: 90px;
      }
    }

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

    /* 导航 */
    .nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: rgba(11, 14, 20, 0.92);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-subtle);
      z-index: 50;
      display: flex;
      align-items: center;
      transition: background 0.3s;
    }

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

    .logo {
      font-size: 20px;
      font-weight: 700;
      color: #FFFFFF;
      text-decoration: none;
      letter-spacing: 0.5px;
      white-space: nowrap;
    }

    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }

    .nav-links a {
      color: var(--text-body);
      text-decoration: none;
      font-size: 15px;
      font-weight: 500;
      padding: 8px 0;
      position: relative;
      transition: color 0.2s;
      white-space: nowrap;
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background-color: var(--gold);
      transition: width 0.25s ease;
    }

    .nav-links a:hover,
    .nav-links a.active {
      color: var(--gold);
    }

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

    /* 移动端底部导航 */
    .mobile-nav {
      display: none;
      position: fixed;
      bottom: 12px;
      left: 12px;
      right: 12px;
      background: var(--surface);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-radius: 20px;
      padding: 8px 16px;
      z-index: 55;
      box-shadow: 0 8px 24px rgba(0,0,0,0.5);
      border: 1px solid var(--border-subtle);
    }

    .mobile-nav-links {
      display: flex;
      justify-content: space-around;
      align-items: center;
      list-style: none;
    }

    .mobile-nav-links a {
      display: flex;
      flex-direction: column;
      align-items: center;
      color: var(--text-muted);
      text-decoration: none;
      font-size: 11px;
      font-weight: 500;
      gap: 4px;
      transition: color 0.2s;
    }

    .mobile-nav-links a svg {
      width: 20px;
      height: 20px;
      stroke: currentColor;
      fill: none;
    }

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

    @media (max-width: 768px) {
      .nav-links {
        display: none;
      }
      .mobile-nav {
        display: block;
      }
    }

    /* 主区块间距 */
    section {
      padding: 100px 0;
    }

    @media (max-width: 768px) {
      section {
        padding: 70px 0;
      }
    }

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

    h1 {
      font-size: 56px;
      font-weight: 700;
      letter-spacing: -0.02em;
      line-height: 1.1;
    }

    h2 {
      font-size: 40px;
      font-weight: 600;
      letter-spacing: -0.01em;
      margin-bottom: 16px;
    }

    h3 {
      font-size: 24px;
      font-weight: 600;
      margin-bottom: 8px;
    }

    @media (max-width: 768px) {
      h1 {
        font-size: 36px;
      }
      h2 {
        font-size: 30px;
      }
    }

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

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

    /* Hero */
    .hero {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 40px;
      min-height: 85vh;
      padding-top: 100px;
    }

    .hero-content {
      flex: 1;
    }

    .hero-image {
      flex: 1;
      position: relative;
      display: flex;
      justify-content: center;
      align-items: center;
    }

    .hero-image img {
      max-width: 100%;
      height: auto;
      opacity: 0.8;
      border-radius: 24px;
      filter: brightness(0.9) contrast(1.1);
    }

    .hero-sub {
      font-size: 18px;
      color: var(--text-body);
      margin: 20px 0 32px;
      line-height: 1.6;
    }

    .btn-primary {
      background: var(--gold);
      color: var(--bg-deep);
      font-weight: 600;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      text-decoration: none;
      display: inline-block;
      transition: background 0.25s, transform 0.2s;
      border: none;
      cursor: pointer;
      font-size: 16px;
      letter-spacing: 0.3px;
    }

    .btn-primary:hover {
      background: var(--gold-hover);
      transform: scale(1.02);
    }

    .btn-text {
      color: var(--gold);
      text-decoration: none;
      font-weight: 500;
      margin-left: 24px;
      position: relative;
      transition: color 0.2s;
    }

    .btn-text::after {
      content: '';
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 0;
      height: 1.5px;
      background: var(--gold);
      transition: width 0.3s ease;
    }

    .btn-text:hover::after {
      width: 100%;
    }

    .client-scroll {
      display: flex;
      gap: 32px;
      margin-top: 48px;
      opacity: 0.7;
      font-size: 14px;
      color: var(--text-muted);
      letter-spacing: 0.5px;
      flex-wrap: wrap;
    }

    @media (max-width: 1024px) {
      .hero {
        flex-direction: column;
        text-align: center;
        min-height: auto;
      }
      .hero-content, .hero-image {
        width: 100%;
      }
      .btn-text {
        margin-left: 0;
        margin-top: 16px;
        display: inline-block;
      }
    }

    /* 指标看板 */
    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
      text-align: center;
    }

    .metric-number {
      font-family: 'Inter', sans-serif;
      font-size: 48px;
      font-weight: 700;
      color: #FFFFFF;
      line-height: 1.2;
    }

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

    @media (max-width: 768px) {
      .metrics-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 24px;
      }
      .metric-number {
        font-size: 36px;
      }
    }

    /* 服务卡片网格 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
      margin-top: 40px;
    }

    .service-card {
      background: var(--surface);
      border-radius: var(--radius-card);
      padding: 32px;
      border: 1px solid var(--border-subtle);
      transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), border-color 0.3s;
      display: flex;
      flex-direction: column;
    }

    .service-card:hover {
      transform: translateY(-4px);
      border-color: var(--border-active);
      box-shadow: 0 8px 30px rgba(0,0,0,0.3);
    }

    .service-icon {
      width: 48px;
      height: 48px;
      margin-bottom: 20px;
      background: transparent;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .service-icon img {
      width: 100%;
      height: 100%;
      object-fit: contain;
    }

    .service-link {
      margin-top: 16px;
      color: var(--gold);
      font-weight: 500;
      text-decoration: none;
      display: inline-flex;
      align-items: center;
      gap: 4px;
    }

    @media (max-width: 1024px) {
      .services-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 640px) {
      .services-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 对比区 */
    .compare-container {
      display: flex;
      gap: 40px;
      margin-top: 40px;
    }

    .compare-col {
      flex: 1;
      background: var(--surface);
      border-radius: var(--radius-card);
      padding: 32px;
      border: 1px solid var(--border-subtle);
    }

    .compare-col h4 {
      margin-bottom: 20px;
      font-size: 20px;
      color: var(--text-muted);
    }

    .compare-col.highlight h4 {
      color: var(--gold);
    }

    .compare-item {
      display: flex;
      justify-content: space-between;
      padding: 12px 0;
      border-bottom: 1px solid rgba(255,255,255,0.05);
    }

    .compare-value {
      font-weight: 600;
      font-size: 18px;
      color: #fff;
    }

    .compare-col.highlight .compare-value {
      color: var(--gold);
    }

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

    /* FAQ */
    .faq-item {
      background: var(--surface);
      border-radius: var(--radius-card);
      margin-bottom: 12px;
      border: 1px solid var(--border-subtle);
      overflow: hidden;
    }

    .faq-question {
      width: 100%;
      background: transparent;
      border: none;
      color: #fff;
      font-size: 18px;
      font-weight: 500;
      padding: 20px 24px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      text-align: left;
    }

    .faq-icon {
      font-size: 24px;
      transition: transform 0.3s;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      padding: 0 24px;
      color: var(--text-body);
    }

    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }

    .faq-item.open .faq-icon {
      transform: rotate(45deg);
    }

    /* 表单 */
    .contact-form {
      display: flex;
      flex-direction: column;
      gap: 20px;
      max-width: 600px;
      margin: 0 auto;
    }

    .form-input {
      background: var(--bg-deep);
      border: 1px solid #2D323B;
      border-radius: var(--radius-btn);
      padding: 14px 16px;
      color: #fff;
      font-size: 16px;
      transition: border-color 0.2s;
      outline: none;
      font-family: var(--font-sans);
    }

    .form-input:focus {
      border-color: var(--gold);
    }

    .trust-badges {
      display: flex;
      justify-content: center;
      gap: 32px;
      margin-top: 24px;
      color: var(--text-muted);
      font-size: 13px;
    }

    /* 页脚 */
    .footer {
      text-align: center;
      padding: 32px 0;
      color: #6B7280;
      font-size: 13px;
      border-top: 1px solid var(--border-subtle);
    }

    /* 动效 */
    .fade-up {
      opacity: 0;
      transform: translateY(24px);
      transition: opacity 0.6s ease, transform 0.6s ease;
    }

    .fade-up.visible {
      opacity: 1;
      transform: translateY(0);
    }