* {
    box-sizing: border-box;
}

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

body {
    padding: 1rem;
    display: flex;
    flex-direction: column;
}

div#js,
div#row {
    height: 50%;
}

div#js,
pre#log {
    border: 2px inset;
    overflow-y: scroll;
}

div#row {
    display: flex;
    flex-direction: row;
    align-items: stretch;
    margin: 1rem 0;
}

h1#out,
pre#log {
    width: 50%;
    margin: 0;
}

h1#out {
    overflow-y: auto;
}

pre#log {
    background: #111;
    color: white;
    padding: 0.25rem;
}