body, html {
    width: 100%;
    height: 100%;
}
body {
    background: #ededed;
    margin: 0;
    padding: 0;
    font-family: 'Roboto', sans-serif;
}
.s404 {
    display: table;
    width: 100%;
    height: 100%;
}
.s404>div {
    display: table-cell;
    width: 100%;
    height: 100%;
    text-align: center;
    vertical-align: middle;
}
.s404>div h1 {
    font-size: 120px;
    font-weight: 300;
    text-align: center;
    color: #666;
}
.back {
    padding: 20px 0 10px;
    font-size: 16px;
    color: #333;
}
.back a {
    color: #007bff;
    text-decoration: underline;
}