#app {
    display: flex;
    flex-direction: column;
    margin: auto;
    max-width: 400px;
}

#app canvas {
    width: 400px;
    height: 400px;
}

#app input,
#app textarea {
    font-size: 1.5em;
    flex: 1 1 auto;
    margin-top: 1em;
}