.region-frozen {
    fill: blue;
}

.region-ok {
    fill: white;
}

.region-warm {
    fill: orange;
}

.region-boiling {
    fill: red;
}

button {
    color: inherit;
    font: inherit;
    margin: 0;
    border: 1px solid;
}

#buttonbar {
    margin: 0 auto;
    text-align: center;
    padding-top: 1em;
}