body {
margin: 0;
padding: 0;
background: yellow;
}

.center {
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%,-50%);
}

input[type="checkbox"] {
position: relative;
width: 80px;
height: 40px;
-webkit-appearance: none;
background: red;
outline: none;
border-radius: 20px;
box-shadow: inset 0 0 5px rgba(0,0,0,0.2);
transition: 0.5s;
}

input:checked[type="checkbox"] {
background: green;
}

input[type="checkbox"]::before {
content: ''; position: absolute;
width: 40px; height: 40px;
border-radius: 20px;
top: 0; left: 0;
background: white;
transform: scale(1.1);
box-shadow: 0 2px 5px rgba(0,0,0,0.2);
transition: 0.5s;
}

input:checked[type="checkbox"]::before {
left: 40px;
}