section.notfound {
    display: flex;
    align-items: center;
}

section.notfound > div {
    padding: 20px;
    margin: 40px auto;
}

section.notfound h3 {
    font-size: 26px;
    margin: 0 0 20px 0;
}

@media (min-width: 479.9px) {
    section.notfound > div:before {
        content: '404';
        position: absolute;
        z-index: -1;
        line-height: 240px;
        font-size: 240px;
        font-weight: bold;
        color: #F7F7F7;
    }
}