body {
    background-color: white;
    width: 800px;
    margin: 0 auto;
}
header{
    background: white;
    padding: 30px;
}
h1:hover{
    transform: rotate(360deg);
    color: firebrick;
    text-align: center;
    transition: all 2s;
}
main {
    background: white;
    padding:30px;
    overflow: auto;
}
footer {
    background: grey;
    padding: 30px;
}
h1 {
    color: black;
    font-family: Verdana;
    text-align: center;
}
strong{
    color: blue;
}
nav a {
    text-decoration: none;
    color: black;
    text-transform: uppercase;
    background-color: whitesmoke;
    padding: 5px 10px;
    display: inline-block;
    margin: 0 1px;
    text-align: center;
}
nav{
    text-align: center;
    background-color: whitesmoke;
}
nav a:hover{
    color:cornflowerblue;
}