css - Apply styles to _root based on JSON object -

this json object.

{   "group": "+display",   "name": "card skin",   "description": "wraps article in card skin.",   "hidden": false,   "id": "skintoggle",   "required": true,   "fieldtype": "boolean",   "defaultvalue": false }, 

what i'd have happen style below applied when card-skin object selected.

_root {     padding: 0; } 

======================

i know

<c:if test="${custom.skintoggle eq true}">     <c:set var="cardskinpadding" value=" card-skin-padding " /> </c:if> 

but i'm having trouble wrapping head around how i'd apply _root.

any appreciated, thank you.