/* 创建新的堆叠上下文，确保背景图可见 */
    html {
      background: var(--bg-light);
    }
    body {
      position: relative;
      background: transparent;
      min-height: 100vh;
    }
    /* 背景图层 - 使用更高优先级 */
    body > .bg-layer,
    body::before {
      content: '';
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      height: 350px;
      background: linear-gradient(to bottom, rgba(0,98,174, 1) 0%, rgba(0,98,174, 0.85) 12vh, rgba(0,74,133, 0.4) 22vh, rgba(0,74,133, 0) 28vh),
                  var(--page-bg-img, url('/fastener/../shared/images/contact-bg.webp')) center center/cover no-repeat;
      z-index: 1;
      pointer-events: none;
    }
    .page-header {
      background: transparent;
    }
    .page-header::before {
      content: none;
      display: none;
    }

    /* ================================
       页面特有的顶部横幅覆盖样式（优化版）
       ================================ */

    /* 定义CSS变量 - 透明状态 */
    .top-bar:not(.scrolled) {
      --header-bg: transparent;
      --header-border: rgba(255, 255, 255, 0.5);
      --header-text: white;
      --header-accent: var(--accent-yellow);
      --header-year: white;
      --header-meta: white;
      --header-btn-bg: rgba(0, 0, 0, 0.3);
      --header-nav-line: white;
      --logo-filter: brightness(0) invert(1);
      backdrop-filter: none;
      -webkit-backdrop-filter: none;
    }

    /* 定义CSS变量 - 白底状态 */
    .top-bar.scrolled {
      --header-bg: rgba(255, 255, 255, 0.98);
      --header-border: var(--border-color);
      --header-text: var(--text-dark);
      --header-accent: var(--primary-blue);
      --header-year: var(--primary-blue);
      --header-meta: var(--text-gray);
      --header-btn-bg: var(--primary-blue);
      --header-nav-line: var(--primary-blue);
      --logo-filter: none;
      box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    }

    /* 应用变量 - 顶部横幅基础样式 */
    .top-bar {
      position: fixed;
      z-index: 1002;
      background: var(--header-bg, rgba(255, 255, 255, 0.95));
      border-bottom: 1px solid var(--header-border, var(--border-color));
      transition: background 0.3s ease, border-color 0.3s ease;
    }

    /* 应用变量 - 文字颜色 */
    .top-bar .top-info-title,
    .top-bar .top-info-item,
    .top-bar .nav-menu a,
    .top-bar .mobile-menu-btn {
      color: var(--header-text, var(--text-dark));
      transition: color 0.3s ease;
    }

    /* 应用变量 - 返回首页按钮 */
    .top-bar .btn-back-home {
      color: var(--header-text, var(--primary-blue));
      border-color: var(--header-text, var(--primary-blue));
    }

    .top-bar .btn-back-home:hover {
      background: var(--header-btn-bg, var(--primary-blue));
      color: var(--header-text, white);
      border-color: var(--header-text, var(--primary-blue));
      transform: translateY(-2px);
    }

    /* 应用变量 - 年份 */
    .top-bar .top-year {
      color: var(--header-year, var(--primary-blue));
    }

    /* 应用变量 - 时间地点 */
    .top-bar .top-info-meta {
      color: var(--header-meta, var(--text-gray));
    }

    /* 应用变量 - 图标 */
    .top-bar .top-info-item i {
      color: var(--header-accent, var(--primary-blue));
    }

    /* 应用变量 - 导航下划线 */
    .top-bar .nav-menu a::after {
      background: var(--header-nav-line, var(--primary-blue));
      transition: width 0.3s ease;
    }

    /* 应用变量 - 返回首页图标（小房子图标） */
    .top-bar .nav-menu li.nav-back-home-item a i {
      color: var(--header-text, var(--primary-blue));
      transition: color 0.3s ease;
    }

    /* 滚动后 - 返回首页图标变为蓝色 */
    .top-bar.scrolled .nav-menu li.nav-back-home-item a i {
      color: var(--primary-blue);
    }

    /* 透明状态下（未滚动）悬停 - 保持白色 */
    .top-bar:not(.scrolled) .nav-menu li.nav-back-home-item a:hover i {
      color: white;
    }

    /* 滚动后悬停 - 变为深蓝色 */
    .top-bar.scrolled .nav-menu li.nav-back-home-item a:hover i {
      color: var(--primary-dark);
    }

    /* 应用变量 - Logo滤镜 */
    @media (max-width: 768px) {
      .top-bar .top-logo img {
        filter: var(--logo-filter, none);
      }

      /* 透明状态下手机端特殊处理 */
      .top-bar:not(.scrolled) .mobile-menu-btn {
        background: rgba(0,0,0,0.2);
      }

      .top-bar.scrolled .mobile-menu-btn {
        background: var(--primary-blue);
      }
    }

    :root {
      --primary-blue: #0062AE;
      --primary-dark: #004A85;
      --accent-yellow: #FFCC00;
      --text-dark: #1A202C;
      --text-gray: #4A5568;
      --text-light: #718096;
      --bg-light: #F7FAFC;
      --bg-white: #FFFFFF;
      --border-color: #E2E8F0;
      --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
      --shadow-lg: 0 10px 25px rgba(0,0,0,0.15);
    }
    
    * { margin: 0; padding: 0; box-sizing: border-box; }
    html{overflow-y:scroll;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;text-rendering:optimizeLegibility;background: var(--bg-light);}
    body { font-family: -apple-system, BlinkMacSystemFont, 'Microsoft YaHei', sans-serif; background: transparent; color: var(--text-dark); line-height: 1.6; -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; }
    
    .page-header {
      position: relative;
      background: transparent;
      z-index: 1;
      color: white;
      height: 350px;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      text-align: center;
      padding-top: 0;
      box-sizing: border-box;
    }

    .page-header h1 { font-size: 42px; margin-bottom: 15px; }
    
    .contact-section { padding: 60px 0; max-width: 1800px; margin: 0 auto; }
    .contact-six-grid { display: grid; grid-template-columns: repeat(6, 1fr); gap: 25px; padding: 0 30px; }
    .contact-six-item { background: white; border-radius: 15px; padding: 40px 25px; box-shadow: var(--shadow-md); transition: all 0.3s; text-align: center; min-height: 200px; }
    .contact-six-item:hover { transform: translateY(-5px); box-shadow: var(--shadow-lg); }
    .contact-six-item .icon { font-size: 48px; margin-bottom: 20px; color: var(--primary-blue); }
    .contact-six-item h3 { font-size: 20px; color: var(--primary-blue); margin-bottom: 15px; }
    .contact-six-item p { color: var(--text-gray); line-height: 1.8; margin-bottom: 10px; font-size: 16px; }
    .contact-six-item p strong { color: var(--text-dark); }
    
    @media (max-width: 768px) {
      .page-header {
        height: 300px;
        justify-content: center;
      }
      
      .page-header h1 { 
        font-size: 32px; 
        margin-top: 80px;
        margin-bottom: 12px;
        font-weight: normal;
        letter-spacing: normal;
        text-shadow: none;
      }
      
      .page-header p {
        font-size: 16px;
        opacity: 0.9;
        font-weight: 400;
        letter-spacing: 2px;
      }
      
      .contact-six-grid { grid-template-columns: repeat(2,1fr); gap: 20px; padding: 0 20px; }
      .contact-six-item { min-height: auto; padding: 30px 20px; }
      .contact-six-item .icon { font-size: 40px; margin-bottom: 15px; }
      .contact-six-item h3 { font-size: 18px; margin-bottom: 15px; }
    }

    /* 模态框表单 */
    .modal-overlay { display: none; position: fixed; top: 0; left: 0; right: 0; bottom: 0; background: rgba(0,0,0,0.6); z-index: 9999; align-items: center; justify-content: center; overflow-y: auto; padding: 20px; }
    .modal-overlay.active { display: flex; }
    .modal-container { background: white; border-radius: 15px; width: 100%; max-width: 800px; max-height: 90vh; overflow-y: auto; position: relative; animation: modalSlideIn 0.3s ease; }
    @keyframes modalSlideIn { from { transform: translateY(-50px); opacity: 0; } to { transform: translateY(0); opacity: 1; } }
    .modal-header { background: linear-gradient(135deg, var(--primary-blue), var(--primary-dark)); color: white; padding: 25px 30px; display: flex; justify-content: space-between; align-items: center; }
    .modal-header h2 { font-size: 28px; font-weight: 700; }
    .modal-close { background: rgba(255,255,255,0.2); border: none; color: white; width: 35px; height: 35px; border-radius: 50%; font-size: 20px; cursor: pointer; transition: background 0.3s; }
    .modal-close:hover { background: rgba(255,255,255,0.3); }
    .modal-body { padding: 30px; }
    .modal-section { margin-bottom: 30px; }
    .modal-section h3 { font-size: 18px; color: var(--primary-blue); margin-bottom: 20px; padding-bottom: 12px; border-bottom: 2px solid var(--border-color); }
    .modal-row { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; margin-bottom: 20px; }
    .modal-group { margin-bottom: 20px; }
    .modal-group.full { grid-column: 1 / -1; }
    .modal-group label { display: block; color: var(--text-dark); font-weight: 600; margin-bottom: 8px; font-size: 14px; }
    .modal-group label .required { color: #e53e3e; margin-left: 5px; }
    .modal-group input, .modal-group textarea, .modal-group select { width: 100%; padding: 12px 14px; border: 2px solid var(--border-color); border-radius: 8px; font-size: 14px; font-family: inherit; transition: border-color 0.3s; }
    .modal-group input:focus, .modal-group textarea:focus, .modal-group select:focus { outline: none; border-color: var(--primary-blue); }
    .modal-group textarea { resize: vertical; min-height: 100px; }
    .modal-submit { width: 100%; padding: 16px; background: linear-gradient(135deg, var(--primary-blue), var(--primary-dark)); color: white; border: none; border-radius: 10px; font-size: 15px; font-weight: 700; cursor: pointer; transition: all 0.3s; margin-top: 20px; }
    .modal-submit:hover { transform: translateY(-2px); box-shadow: 0 10px 25px rgba(0,98,174,0.3); }
    .modal-success { display: none; background: #c6f6d5; color: #22543d; padding: 20px; border-radius: 10px; margin-bottom: 25px; text-align: center; }
    .modal-success.show { display: block; }
    @media (max-width: 768px) { .modal-row { grid-template-columns: 1fr; } }