style.css

/* https://stackoverflow.com/questions/19461521/how-to-center-an-element-horizontally-and-vertically#:~:text=For%20vertical%20alignment%2C%20set%20the,any%20other%20inline%20children%20elements */
canvas {
    position: absolute;
    top: 50%;
    left: 50%;
    -moz-transform: translateX(-50%) translateY(-50%);
    -webkit-transform: translateX(-50%) translateY(-50%);
    transform: translateX(-50%) translateY(-50%);
    border-radius: 5px;
}

/* https://css-tricks.com/almanac/properties/b/box-shadow/ */
canvas {
    box-shadow: 0 2.8px 2.2px rgba(0, 0, 0, 0.034),
                0 6.7px 5.3px rgba(0, 0, 0, 0.048),
                0 12.5px 10px rgba(0, 0, 0, 0.06),
                0 22.3px 17.9px rgba(0, 0, 0, 0.072),
                0 41.8px 33.4px rgba(0, 0, 0, 0.086),
                0 100px 80px rgba(0, 0, 0, 0.12);
}