html{
    margin: 10px;
    padding: 10px;
    text-align: center;
    color: white;
    background-color: #333;
}
ul.header{
    list-style: none;
    top: 0;
    position: relative;
    text-align: center;
    background-color: #787878;
    margin-left: 10%;
    margin-right: 10%;
}
ul.header li a{
    color: black;
    text-decoration: none;
}
a{
    color: white;
}