<html>
<head>
<style>
* {
box-sizing: border-box;
}
.header, .footer {
background-color: grey;
color: white;
padding: 15px;
}
.column {
float: left;
padding: 15px;
}
.clearfix::after {
content: "";
clear: both;
display: table;
}
.menu {
width: 25%;
}
.content {
width: 75%;
}
.menu ul {
list-style-type: none;
margin: 0;
padding: 0;
}
.menu li {
padding: 8px;