/* 底部导航样式 - 与原燃料成分导航一致 */
        .bottom-nav {
            position: fixed;
            bottom: 0;
            left: 0;
            right: 0;
            display: flex;
            justify-content: space-around;
            background-color: white;
            padding: 10px 0;
            box-shadow: 0 -2px 5px rgba(0,0,0,0.1);
            z-index: 100;
        }
        
        .nav-item {
            display: flex;
            flex-direction: column;
            align-items: center;
            text-decoration: none;
            color: #666;
            font-size: 12px;
            position: relative;
        }
        
        .nav-icon {
            width: 24px;
            height: 24px;
            margin-bottom: 4px;
        }
        
        .badge {
            position: absolute;
            top: -5px;
            right: -5px;
            background-color: red;
            color: white;
            border-radius: 50%;
            width: 16px;
            height: 16px;
            font-size: 10px;
            display: flex;
            align-items: center;
            justify-content: center;
        }