input[type="checkbox"] + span,
input[type="checkbox"] + span::before
{
    display: inline-block;
    vertical-align: middle;
}
 
label *
{
    cursor: pointer;
}
 
input[type="checkbox"]
{
    opacity: 0;
    position: absolute;
}
 
input[type="checkbox"] + span
{
    font: normal 11px/14px Arial, Sans-serif;
    color: #fff;
}
 
label:hover span::before
{
    -moz-box-shadow: 0 0 2px #fff;
    -webkit-box-shadow: 0 0 2px #fff;
    box-shadow: 0 0 2px #fff;
}
 
label:hover span
{
    color: #fff;
}
 
input[type="checkbox"] + span::before
{
    content: "";
    width: 12px;
    height: 12px;
    margin: 0 4px 0 0;
    border: solid 1px #999;
    line-height: 14px;
    text-align: center;
     
    -moz-border-radius: 100%;
    -webkit-border-radius: 100%;
    border-radius: 100%;
}
 
input[type="checkbox"]:checked + span::before
{
    color: #999;
}

input[type="checkbox"]:disabled + span
{
    cursor: default;
    -moz-opacity: .4;
    -webkit-opacity: .4;
    opacity: .4;
}
 
input[type="checkbox"] + span::before
{
    -moz-border-radius: 2px;
    -webkit-border-radius: 2px;
    border-radius: 2px;
}
 
 
input[type="checkbox"]:checked + span::before
{
    content: "\2714";
    font-size: 12px;
}

/* Highlight modifications */
.highlight input[type="checkbox"] + span::before
{
    content: "";
    width: 12px;
    height: 12px;
    margin: 0 4px 0 0;
    border: solid 1px white;
    line-height: 14px;
    text-align: center;
     
    -moz-border-radius: 100%;
    -webkit-border-radius: 100%;
    border-radius: 100%;
}
 
.highlight input[type="checkbox"]:checked + span::before
{
    color: white;
}

.highlight input[type="checkbox"]:disabled + span
{
    cursor: default;
    -moz-opacity: .4;
    -webkit-opacity: .4;
    opacity: .4;
}
 
.highlight input[type="checkbox"] + span::before
{
    -moz-border-radius: 2px;
    -webkit-border-radius: 2px;
    border-radius: 2px;
}
 
 
.highlight input[type="checkbox"]:checked + span::before
{
    content: "\2714";
    font-size: 12px;
}