1.container input {
2  position: absolute;
3  opacity: 0;
4  cursor: pointer;
5  height: 0;
6  width: 0;
7}
8
9.container {
10  position: relative;
11  cursor: pointer;
12  font-size: 17px;
13  width: 2em;
14  height: 2em;
15  user-select: none;
16  border: 5px solid white;
17}
18
19.checkmark {
20  position: absolute;
21  top: 0;
22  left: 0;
23  width: 100%;
24  height: 100%;
25}
26
27.checkmark:after {
28  content: '';
29  position: absolute;
30  top: 25%;
31  left: 25%;
32  background-color: white;
33  width: 50%;
34  height: 50%;
35  transform: scale(0);
36  transition: .1s ease;
37}
38
39.container input:checked ~ .checkmark:after {
40  transform: scale(1);
41}