html, body {
    height: 100%;
    width: 100%;
    padding: 0;
    margin: 0;
}

#weather {
    display: block;
    margin: auto;
    height: 60vh;
}

#datetime {
    display: block;
    width: 100%;
    height: 15vh;
    text-align: center;
    line-height: 15vh;
}
#datetime span {
    display: inline-block;
    vertical-align: middle;
    line-height: 8vh;
    font-size: 8vh;
}