#canvas, #keys {
    text-align: center;
    margin: 20px auto;
}
canvas {
    border: 1px solid #ccc;
    border-radius: 5px;
}
#canvas-title {
    text-align: center;
    color: #00f;
}

#keys {
    width: 300px;
    border: 1px solid #ccc;
    text-align: center;
}
#keys .arrow {
    width: 50px;
    height: 50px;
    border: 1px solid #ccc;
    border-radius: 5px;
    display: inline-block;
    margin: 5px;
    cursor: pointer;
}
#keys .arrow span {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100%;
}
#keys .arrow.pressed {
    background-color: #ddd;
    box-shadow: inset 3px 3px 5px #aaa;
}