Initially posted here.
input[type="checkbox"] {_x000D_
cursor: pointer;_x000D_
-webkit-appearance: none;_x000D_
-moz-appearance: none;_x000D_
appearance: none;_x000D_
outline: 0;_x000D_
background: lightgray;_x000D_
height: 16px;_x000D_
width: 16px;_x000D_
border: 1px solid white;_x000D_
}_x000D_
_x000D_
input[type="checkbox"]:checked {_x000D_
background: #2aa1c0;_x000D_
}_x000D_
_x000D_
input[type="checkbox"]:hover {_x000D_
filter: brightness(90%);_x000D_
}_x000D_
_x000D_
input[type="checkbox"]:disabled {_x000D_
background: #e6e6e6;_x000D_
opacity: 0.6;_x000D_
pointer-events: none;_x000D_
}_x000D_
_x000D_
input[type="checkbox"]:after {_x000D_
content: '';_x000D_
position: relative;_x000D_
left: 40%;_x000D_
top: 20%;_x000D_
width: 15%;_x000D_
height: 40%;_x000D_
border: solid #fff;_x000D_
border-width: 0 2px 2px 0;_x000D_
transform: rotate(45deg);_x000D_
display: none;_x000D_
}_x000D_
_x000D_
input[type="checkbox"]:checked:after {_x000D_
display: block;_x000D_
}_x000D_
_x000D_
input[type="checkbox"]:disabled:after {_x000D_
border-color: #7b7b7b;_x000D_
}
_x000D_
<input type="checkbox"><br>_x000D_
<input type="checkbox" checked><br>_x000D_
<input type="checkbox" disabled><br>_x000D_
<input type="checkbox" disabled checked><br>
_x000D_