textarea {
    font-family: monospace;
}
header {
    font-size: 130%;
    font-weight: bold;
}
.hidden, .initially-hidden {
    position: absolute !important;
    opacity: 0 !important;
    pointer-events: none !important;
    display: none !important;
}
fieldset.options {
    font-size: 75%;
}
fieldset > legend {
    padding: 0 0.5em;
}
span.labeled-input {
    padding: 0.25em;
    margin: 0.25em 0.5em;
    border-radius: 0.25em;
    white-space: nowrap;
    background: #0002;
}
.center { text-align: center; }
.error {
    color: red;
    background-color: yellow;
}
#test-output { font-family: monospace }