The checkbox has the following options:

theme string

default: null, inherited from parent

Sets the theme swatch color scheme for the checkbox. This is a single letter from a-z that maps to the swatches included in your theme. By default, a checkbox will inherit the same swatch color as it's parent container if not explicitly set. This option is also exposed as a data attribute: data-theme="a"

$("input[type='checkbox'").checkboxradio({ theme: "a" });