body {
    margin: 0;
    padding: 0;
    font-family: "Times New Roman", Times, serif;
    width: 100%;
}
.header {
    background-color: #666;
    color: white;
    text-align: center;
    font-size: 35px;
    padding: 20px 0; 
}
.nav {
    float: left;
    width: 30%;
    height: 300px;
    background-color: #cccccc;
    padding: 20px;
    box-sizing: border-box;
}
.article {
    float: left;
    width: 70%;
    height: 300px;
    background-color: #f1f1f1;
    padding: 20px;
    box-sizing: border-box;
}
.footer {
    clear: both;
    background-color: #666;
    color: white;
    text-align: center;
    padding: 10px 0;
}
ul {
    list-style-type: none;
    padding: 0;
}
ul li a {
    color: blue;
    text-decoration: none;
    font-size: 18px;
}