html, body {
  margin: 0;
  padding: 0;
}
canvas {
  display: block;
}
#header {
    width: 100%;
    background-color: red;
    height: 30px;
    color: white;
    margin: auto;
    text-align: center;
}

#container {
    width: 700px;
    height: 800px;
    background-color: #ffcc33;
    margin: auto;
    border: solid 1px;
}
#zeroth {
    width: 400px;
    float: left;
    background-color: #fffff0;
}
#first {
    width: 100px;
    float: left;
    height: 300px;
        background-color: blue;
    color: white;
}
#first-responsive {
    max-width: 300px;
    height: 300px;
        background-color: blue;
    color: white;
}
#second1 {
    width: 200px;
    float: left;
    height: 300px;
    background-color: green;
}
#clear {
    clear: both;
}
 .myCode { /* used to display code snippets */
            font-family: monospace;
            font-size: 15px;
            color: darkgreen;
            line-height: 1.6;
            margin-bottom: 1.6em;
            max-width: 100%;
            overflow: auto;
       }