xray-viewer/xray.css

html, body {
    font-family: sans-serif;
    width: 100vw;
    height: 100vh;
    margin: 0;
    display: flex;
    flex-direction: column;
    background: #111;
    color: #ddd;
}

input,
button {
    background: #111;
    color: #ddd;
}
canvas {
    position: absolute;
}

canvas.hidden {
    display: none;
}

img {
    display: none;
}

#overlay {
    z-index: 1;
}

#menu {
    display: flex;
    flex: 0 1;
    flex-direction: row;
    transition: 0.5s;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
}

#menu.start {
    flex-direction: column;
    min-width: 100vw;
    min-height: 100vh;
    justify-content: center;
}

#menu.start input {
    font-size: 24pt;
}

#menu.start label,
#menu.start button {
    font-size: 48pt;
    margin: 16pt;
}

#menu.start input {
    width: 80vw;
}

#menu.start .nostart {
    display: none;
}

#menu .onlystart {
    display: none;
}

#menu.start .onlystart {
    display: unset;
}

.large,
.large > * {
    font-size: 24pt;
}

.large > input[type=number] {
    max-width: 72pt;
}

.large > input[type=checkbox] {
    width: 1em;
    height: 1em;
}

#fill-div {
    position: relative;
    flex: 1 0;
}