input[type="checkbox"] + span{
    -webkit-appearance: none;
    appearance: none;
    width: 40px;
    height: 40px;
    border: none;
    background-color: #fff;
    outline: none;
    box-sizing: border-box;
    display: inline-block;
    cursor: pointer;
}

input[type="checkbox"]:checked + span:before{
    content: "";
    display: block;
    width: 16px;
    height: 32px;
    border: 0 solid #138DA5;
    border-width: 0 4px 4px 0;
    -webkit-transform: rotateZ(45deg);
    transform: rotateZ(45deg);
    margin: -2px 12px;
    pointer-events: none;
}