Checkbox Not Appearing Correctly On Mobile Devices

Go to style.css for edit, and remove the lines between 4303-4318;

/*    Retina media query.
    Overrides styles for devices with a 
    device-pixel-ratio of 2+, such as iPhone 4.
-----------------------------------------------    */
@media 
    only screen and (-webkit-min-device-pixel-ratio: 2),
    only screen and (min-device-pixel-ratio: 2) {
    input, textarea, button, select {
        -webkit-appearance: none; /*Safari/Chrome*/
        -moz-appearance: none; /*Firefox*/
        -ms-appearance: none; /*IE*/
        -o-appearance: none; /*Opera*/
        appearance: none;    
        -webkit-border-radius: 0;
    }    
}

Make sure the lines look likes block above.