#playground-in, #playground-out, #playground-message {
    box-sizing: border-box;
    width: 100%;
    margin: 0;
    font-size: inherit;
    border: 8px solid #888;
}
#playground-in {
    border-bottom: 1px dashed #888;
    --padding: 20px; /* for code-input elements */
}
#playground-out, #playground-message {
    border-top: 1px dashed #888;
}
#playground-in, #playground-out {
    height: min(400px, calc(50vh - 65px));
    resize: vertical;
}
#playground-out {
    background-color: white;
}
#playground-message {
    position: static;
    padding: 20px;

    background: transparent;
    color: inherit;
}
#playground-message input[type=submit] {
    font-size: 200%;
}