body {
        background-color: lightgray;
        font-family: Arial, Helvetica, sans-serif;
    }

    #container {
        width: 1100px;
        margin: 0px auto;
        border: 4px solid gray;
    }
    header {
        background-color: red;
        height: 100px;
        width: 100%;
        margin: 0px;
        text-align: center;
        line-height: 100px;
        color: antiquewhite;
        border-bottom: 2px solid black;
    }
    nav ul li {
        float: left;
        list-style: none;
        margin: 20px;
        line-height: 10px;
    }
    ul {
        text-align: center;
        display: inline-block;
        background-color: aquamarine;
    }
    a {
        text-decoration: none;
    }
    #content {
        float: left;
        width: calc(80% - 20px);
        background-color: green;
        min-height: 500px;
        padding: 10px;
    }
    .article {
        color: white;
        margin-top: 15px;
        margin-bottom: 15px;
        border-bottom: 1px solid white;
        padding-bottom: 20px;
    }
    aside {
        float: left;
        width: calc(20% - 20px);
        background-color: coral;
        min-height: 750px;
        padding: 10px;
    }
    footer {
        background-color: black;
        color: white;
        text-align: center;
        height: 30px;
        line-height: 30px;
    }
    .clearfix {
        clear: both;
    }
    * {
        margin: 0px;
        padding: 0px;
    }