1 
2<label class="container">
3  <input checked="checked" type="checkbox">
4  <div class="checkmark"></div>
5</label>          

 1 
 2/* Hide the default checkbox */
 3.container input {
 4 position: absolute;
 5 opacity: 0;
 6 cursor: pointer;
 7 height: 0;
 8 width: 0;
 9}
10 
11.container {
12 display: block;
13 position: relative;
14 cursor: pointer;
15 font-size: 25px;
16 user-select: none;
17}
18 
19/* Create a custom checkbox */
20.checkmark {
21 position: relative;
22 top: 0;
23 left: 0;
24 height: 1.3em;
25 width: 1.3em;
26 background: black;
27 border-radius: 50px;
28 transition: all 0.7s;
29 --spread: 20px;
30}
31 
32/* When the checkbox is checked, add a blue background */
33.container input:checked ~ .checkmark {
34 background: black;
35 box-shadow: -10px -10px var(--spread) 0px #5B51D8, 0 -10px var(--spread) 0px #833AB4, 10px -10px var(--spread) 0px #E1306C, 10px 0 var(--spread) 0px #FD1D1D, 10px 10px var(--spread) 0px #F77737, 0 10px var(--spread) 0px #FCAF45, -10px 10px var(--spread) 0px #FFDC80;
36}
37 
38/* Create the checkmark/indicator (hidden when not checked) */
39.checkmark:after {
40 content: "";
41 position: absolute;
42 display: none;
43}
44 
45/* Show the checkmark when checked */
46.container input:checked ~ .checkmark:after {
47 display: block;
48}
49 
50/* Style the checkmark/indicator */
51.container .checkmark:after {
52 left: 0.45em;
53 top: 0.25em;
54 width: 0.25em;
55 height: 0.5em;
56 border: solid #f0f0f0;
57 border-width: 0 0.15em 0.15em 0;
58 transform: rotate(45deg);
59}