* {   
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
body {
    font-family: Arial, sans-serif;
    box-sizing: border-box;
    background-color: #212121;
    color: white;
}
header, footer  {
        text-align: center;
        background-color: #243B53;
}
footer {
    position: fixed;
    bottom: 0;
    width: 100%;
    padding: 2px;
}
h1  {
    font-size: 80px;
    padding: 5px;
}
nav {
    background: #243B53;  
}
nav a {
    color: #b9b9b9;
    background: #243B53;
    text-decoration: none;
    display: block;
    padding: 5px;
}
nav a:hover {
        color: #ffffff;
        transition: 200ms;
    }
@media screen and (max-width: 600px) {
        nav {
            width: 100%;
        }
        footer {
            position: fixed;
        }
    }