html, body {
height: 100%;
margin: 0px;
}

#header {
height: 80px;
background-color: slategrey;
color: salmon;
line-height: 80px;
text-align: center;
}

#nav {
line-height: 30px;
background-color: orchid;
height: calc(100% - 100px);
width: 80px;
float: left;
}

#nav a {
 color: #111;
 display: block;
 padding: 10px;
 background-color: blue;
 text-decoration: none;
}

#nav a:hover {
    background-color: tomato;
    color: lightgray;
    text-decoration: underline;
}

#main {
width: 600px;
padding: 20px;
float: left;
}

#footer {
height: 20px;
background-color: lightskyblue;
color: white;
text-align: center;
clear: both;
}

.caption {
background-color: #111;
color: white;
text-align: right;
font-family: arial, sans-serif;
font-size: 9px;
padding: 5px;
}

.caption a {
color: white;
}