<input id=un type=checkbox> <label for=un>un</label>
	<input id=deux type=checkbox checked> <label for=deux>deux</label>
	<input id=trois type=checkbox> <label for=trois>trois</label>
	<input id=quatre type=checkbox> <label for=quatre>quatre</label>
	width: 40px; height: 40px;
	border-radius: 50%;
	transition: box-shadow .3s;
	background: lightgrey;
	cursor: pointer;
	border: 0;
	appearance: none; -webkit-appearance: none; 

input:checked{ box-shadow: inset 0 0 0 20px blue; }

	display: grid;
	grid:  repeat(4, 100px) / 90px 1fr;
	align-items: center;
	width: max-content;
	font: 60px Girassol;
	color: lime;
	text-shadow: 2px 2px 0 blue;
	cursor: pointer;
	display: grid;
	height: 100vh;
	align-items: center; 
	justify-items: center;
	user-select: none; -webkit-user-select:  none;
	-webkit-tap-highlight-color: transparent;

/* You can also try multiple shadow values if there's some level of transparency between the shadow colors. You can get that transparency with rgba() color values. */

External CSS

  1. https://fonts.googleapis.com/css2?family=Girassol&amp;display=swap

External JavaScript

This Pen doesn't use any external JavaScript resources.