.content {
    max-width: 500px;
    margin: auto;
}
.center {
    display: block;
    margin-left: auto;
    margin-right: auto;
    width: 30%;
}
.footer {
    position: fixed;
    left: 0;
    bottom: 0;
    width: 100%;
    background-color:white;
    color: black;
    text-align: center;
}