* {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }
        
        body {
            font-family: Arial, sans-serif;
            color: #333;
            line-height: 1.6;
            max-width: 1000px;
            margin: 0 auto;
            padding: 20px;
        }
        
        .container {
            width: 100%;
            border: 1px solid #999;
        }
        
        .header {
            width: 100%;
            padding: 20px;
            text-align: center;
            border-bottom: 1px solid #999;
            color: green;
        }
        
        .nav {
            width: 100%;
            padding: 20px;
            text-align: center;
            border-bottom: 1px solid #999;
            color: green;
        }
        
        .content-wrapper {
            width: 100%;
            overflow: auto;
        }
        
        .sidebar-left {
            width: 20%;
            padding: 100px 20px;
            text-align: center;
            border-right: 1px solid #999;
            float: left;
            height: 300px;
            color: green;
        }
        
        .main-content {
            width: 60%;
            padding: 100px 20px;
            text-align: center;
            border-right: 1px solid #999;
            float: left;
            height: 300px;
            color: green;
        }
        
        .sidebar-right {
            width: 20%;
            padding: 100px 20px;
            text-align: center;
            float: left;
            height: 300px;
            color: green;
        }
        
        .footer {
            width: 100%;
            clear: both;
            padding: 20px;
            text-align: center;
            border-top: 1px solid #999;
            color: green;
        }