HTML input checkbox as a switch button with css variables

checkbox-switch.css

/*
   Checkbox input as a switch
   ---------------------------------------------------------- */

.switch {
    --width: 60px;
    --height: 34px;
    --gutter: 4px;
    --dot-width: calc(var(--height) - (var(--gutter) * 2));
    --dot-color: #fff;
    --color-on: #2196F3;
    --color-off: #ccc;
    position: relative;
    display: inline-block;
    vertical-align: middle;
    width: var(--width);
    height: var(--height);
    cursor: pointer;
}
.switch input {
    display: none;
}
.switch i {
    display: block;
    height: 100%;
    background-color: var(--color-off);
    border-radius: var(--height);
    transition: .2s;
}
.switch i:before {
    position: absolute;
    left: var(--gutter);
    bottom: var(--gutter);
    content: "";
    width: var(--dot-width);
    height: var(--dot-width);
    border-radius: var(--dot-width);
    background: var(--dot-color);
    transition: .2s;
}
.switch input:checked + i {
    background-color: var(--color-on);
}
.switch input:checked + i:before {
    transform: translateX(calc(var(--width) - (var(--gutter) * 2) - var(--dot-width)));
}

checkbox-switch.html

<label class="switch"><input type="checkbox" autocomplete="off"><i></i></label>