HTML
<ion-item>
<ion-label>Daenerys Targaryen</ion-label>
<ion-checkbox color="dark" checked="true"></ion-checkbox>
</ion-item>
scss
.checkbox-icon {
border-color: #999 !important;
background-color: #fff!important;
}
.checkbox-checked {
background-color: #a71818!important;
border-color: #a71818 !important;
}