header
{
    background: silver;
    color: navy;
    text-align: center;
}

.menu
{
    background-color: silver;
    float: left;
    width: 20vw;
    height: 50vh;
}

.content
{
    background-color: silver;
    float: right;
    width: 78vw;
    height: 50vh;
}