style.css

body {
    margin: 0 auto;
    padding: 1em;
    background-color: #C2CAD0; 
}
h1, h2, h3, a {
    color: #7E685A;
}
.header img {
    float: left;
    margin-right: 1em;
}
.nav {
    float: right;
}
.nav ul, footer ul {
    list-style-type: none;
}
.nav li {
    display: inline-block;
    margin-right: 1.5em;
    font-size: 1.5em;
    text-transform: uppercase;
}
.section {
    padding: 1em;
    width: 50%;
    float: left;
    box-sizing: border-box;
}
.aside-left {
    background-color: #AFD275;
    border: 0.1em solid #334499;
    padding: 1em;
    width: 25%;
    float: left;
    box-sizing: border-box;
}
.aside-left img {
    max-width: 100%;
}
.aside-right {
    background-color: #AFD275;
    border: 0.1em solid #334499;
    padding: 1em;
    width: 25%;
    float: right;
    box-sizing: border-box;
}
.aside-right img {
    max-width: 100%;
}
.footer:before {
    content: "";
    display: table;
    clear: both;
}
.footer {
    width: 100%;
    text-align: center;
}
.footer li {
    display: inline-block;
    margin-right: 1.5em;
}