*{
    box-sizing: border-box;
    padding: 0;
    margin: 0;
}
body {
    background-color: #ddd;
    display:grid;
    grid-template-areas: "canvas canvas canvas"
        "canvas canvas canvas"
        "debug controls controls";
    height: 100vh;
}
body > {
    display:grid;
}
canvas{
    height: 100%;
    width: 100%;
}