html, body {
    margin: 0;
    padding: 0;
    height: 100%;
    font-family: 'Arcade', arial;
    font-size: 30px;
}

#main {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.slider {
    width: 100px;
}

#help {
    position: absolute;
}