* { box-sizing: border-box; margin: 0; padding: 0; }
        body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif; color: #333; line-height: 1.5; }
        a { text-decoration: none; color: inherit; }
        ul { list-style: none; }

        /* 头部导航栏 Header */
        .site-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 10px 40px;
            background-color: #ffffff;
            box-shadow: 0 1px 3px rgba(0,0,0,0.05);
        }
        .header-left {
            display: flex;
            align-items: center;
        }
        .header-logo {
            height: 32px;
            width: auto;
            /* 紧邻排列，控制微小且紧凑的专业间距 */
            margin-right: 15px; 
            display: block;
        }
        .nav-list {
            display: flex;
            align-items: center;
            gap: 20px; /* 导航文字之间的间距 */
            font-size: 14px;
            font-weight: 500;
        }
        .nav-list a:hover { color: #24A1DE; }
        .header-right {
            display: flex;
            align-items: center;
        }
        .x-bird-icon {
            height: 24px;
            width: auto;
            display: block;
        }

        /* 页面主体包裹层（确保页脚置底） */
        .main-wrapper {
            min-height: calc(100vh - 52px - 160px); /* 动态减去头部和页脚高度 */
            padding: 40px;
        }

        /* 页脚 Footer */
        .site-footer {
            background-color: #f8f9fa;
            border-top: 1px solid #eaeaea;
            padding: 25px 40px;
            font-size: 13px;
            color: #666;
        }
        .footer-content {
            display: flex;
            flex-direction: column;
            align-items: center;
            text-align: center;
            gap: 12px;
        }
        .footer-logo-area {
            display: flex;
            align-items: center;
            gap: 10px;
        }
        .footer-logo {
            height: 24px; /* 限制高度的 Logo 图标 */
            width: auto;
        }
        .footer-text {
            font-weight: 400;
        }
        .footer-links {
            display: flex;
            gap: 15px;
        }
        .footer-links a {
            color: #444;
            transition: color 0.2s;
        }
        .footer-links a:hover { color: #24A1DE; }
        .copyright {
            font-size: 12px;
            color: #999;
        }