1 
 2<label class="container">
 3  <input type="checkbox" checked="checked">
 4  <svg class="bell-regular" xmlns="http://www.w3.org/2000/svg" height="1em" viewBox="0 0 448 512">
 5    <path d="M224 0c-17.7 0-32 14.3-32 32V49.9C119.5 61.4 64 124.2 64 200v33.4c0 45.4-15.5 89.5-43.8 124.9L5.3 377c-5.8 7.2-6.9 17.1-2.9 25.4S14.8 416 24 416H424c9.2 0 17.6-5.3 21.6-13.6s2.9-18.2-2.9-25.4l-14.9-18.6C399.5 322.9 384 278.8 384 233.4V200c0-75.8-55.5-138.6-128-150.1V32c0-17.7-14.3-32-32-32zm0 96h8c57.4 0 104 46.6 104 104v33.4c0 47.9 13.9 94.6 39.7 134.6H72.3C98.1 328 112 281.3 112 233.4V200c0-57.4 46.6-104 104-104h8zm64 352H224 160c0 17 6.7 33.3 18.7 45.3s28.3 18.7 45.3 18.7s33.3-6.7 45.3-18.7s18.7-28.3 18.7-45.3z"></path>
 6  </svg>
 7  <svg class="bell-solid" xmlns="http://www.w3.org/2000/svg" height="1em" viewBox="0 0 448 512">
 8    <path d="M224 0c-17.7 0-32 14.3-32 32V51.2C119 66 64 130.6 64 208v18.8c0 47-17.3 92.4-48.5 127.6l-7.4 8.3c-8.4 9.4-10.4 22.9-5.3 34.4S19.4 416 32 416H416c12.6 0 24-7.4 29.2-18.9s3.1-25-5.3-34.4l-7.4-8.3C401.3 319.2 384 273.9 384 226.8V208c0-77.4-55-142-128-156.8V32c0-17.7-14.3-32-32-32zm45.3 493.3c12-12 18.7-28.3 18.7-45.3H224 160c0 17 6.7 33.3 18.7 45.3s28.3 18.7 45.3 18.7s33.3-6.7 45.3-18.7z"></path>
 9  </svg>
10</label>          

 1 
 2/*------ Settings ------*/
 3.container {
 4  --color: #a5a5b0;
 5  --size: 30px;
 6  display: flex;
 7  justify-content: center;
 8  align-items: center;
 9  position: relative;
10  cursor: pointer;
11  font-size: var(--size);
12  user-select: none;
13  fill: var(--color);
14}
15 
16.container .bell-regular {
17  position: absolute;
18  animation: keyframes-fill .5s;
19}
20 
21.container .bell-solid {
22  position: absolute;
23  display: none;
24  animation: keyframes-fill .5s;
25}
26 
27/* ------ On check event ------ */
28.container input:checked ~ .bell-regular {
29  display: none;
30}
31 
32.container input:checked ~ .bell-solid {
33  display: block;
34}
35 
36/* ------ Hide the default checkbox ------ */
37.container input {
38  position: absolute;
39  opacity: 0;
40  cursor: pointer;
41  height: 0;
42  width: 0;
43}
44 
45/* ------ Animation ------ */
46@keyframes keyframes-fill {
47  0% {
48    opacity: 0;
49  }
50 
51  25% {
52    transform: rotate(25deg);
53  }
54 
55  50% {
56    transform: rotate(-20deg) scale(1.2);
57  }
58 
59  75% {
60    transform: rotate(15deg);
61  }
62}