body {
    background: darkgrey;
    padding-top: 50px;
    padding-bottom: 50px;
    margin-left: auto;
    margin-right: auto;
    width: 10vw;
    min-height:  calc(100vh - 100px);
    margin-top: 0;
    margin-bottom:0;
}

hr {
    width: 100%;
}

section {
    width: 90%;
}