crtjs/css/style.css

html,
body {
	--size: 50px;
	margin: 0;
	overflow: hidden;
	background: gray;
}

html {
	height: 100%;
	display: flex;
	justify-content: center;
	align-items: center;
}

body {
	--resolution: 200px;
	width: calc(var(--size) * 4);
	height: calc(var(--size) * 5);
	background: black;
}

#electron {
	position: absolute;
	width: var(--size);
	height: var(--size);
	background: red;
	/*animation: interpolate 1ms linear infinite;*/
}

@keyframes interpolate {
	to {
		box-shadow: 
			0 -20px 0 red, 0 20px 0 red, /* y 1 */
			0 -40px 0 red, 0 40px 0 red, /* y 2 */
			0 -80px 0 red, 0 80px 0 red, /* y 3 */
			0 -100px 0 red, 0 100px 0 red, /* y 4 */
			-20px 0 0 red, 20px 0 0 red, /* x 1 */
			-40px 0 0 red, 40px 0 0 red, /* x 2 */
			-80px 0 0 red, 80px 0 0 red, /* x 3*/
			-100px 0 0 red, 100px 0 0 red; /* x 4 */
	}
}