style.css

body {
    background-color: #4C4C4C;
    margin-top: 72px;
    margin-left: 122px;
    margin-right: 20px;
    margin-bottom: 20px;
    height: 100%;
}

nav {
    left: 0px;
    top: 0px;
    height: 40px;
    width: 100%;
    padding: 5px;
    position: fixed;
    background-color: #383838;
    color: white;
    border-bottom: 2px solid #22EE5B;
    text-align: center;
    font-size: 25px;
    overflow-x: auto;
    overflow-y: hidden;
}

nav img { vertical-align: middle; }

nav ul { display: inline; }

nav li {
    display: inline;
    padding: 5px;
    margin: 0px;
}

nav li:hover {
    background-color: #242424;
    border-top: 10px #242424 solid;
    border-bottom: 10px #242424 solid;
}

nav #current {
    background-color: #02AAD1;
    border-top: 10px #02AAD1 solid;
    border-bottom: 10px #02AAD1 solid;
}

nav #impossible {
    background-color: #02AAD1;
    border-top: 10px #02AAD1 solid;
    border-bottom: 10px #02AAD1 solid;
}

nav a {
    text-decoration:none;
    color: white;
}

nav a:hover { text-decoration: underline; }

nav .first {
    width: 100px;
    left: 0px;
    top: 0px;
    height: 50px;
    position: fixed;
    background-color: #242424;
}

nav .second {
    width: 100px;
    left: 0px;
    top: 50px;
    height: 100%;
    position: fixed;
    background-color: #383838;
    color: white;
    text-align: center;
    font-size: 25px;
    border-right: 2px solid #22EE5B;
}

header, footer, section, article, aside { border: 2px solid #FF5353; }

header, footer {
    padding: 5px;
    margin-bottom: 20px;
}

section {
    margin-bottom: 20px;
    padding: 20px;
}

article {
    margin-right: 274px;
}

aside {
    width: 250px;
    position: absolute;
    right: 42px;
    top: 148px;
}