.bapf_ckbox_greychck input[type=checkbox] {
    -webkit-appearance: none;
    -moz-appearance: none;
    -ms-appearance: none;
    appearance: none;
    display: inline-block;
    vertical-align: middle;
    border: 0;
    border: 1px solid #ddd;
    background-color: #ddd;
    width: 20px;
    height: 20px;
    outline: none;
    padding: 4px;
    margin-right: 5px;
    position: relative;
}

.bapf_ckbox_greychck input[type="checkbox"]:checked {
    border: 1px solid #555;
    background-color: transparent;
}
.bapf_ckbox_greychck input[type="checkbox"]:checked:after {
    content: "";
    width: 8px;
    height: 10px;
    border-bottom: 2px solid #333;
    border-right: 2px solid #333;
    display: block;
    position: absolute;
    top: 2px;
    left: 5px;
    transform: rotate(45deg);
}