<style> 
  INPUT:checked + label {color: #00F;} 
</style>

<input id="theId" type="checkbox"><label for="theId"> The cat is here</label> 
<fieldset style="width:fit-content"><legend>Where is the Cat?</legend>
	<input id="cat_garden" name="cat_where" type="radio"><label for="cat_garden"> Garden</label> 
	<input id="cat_bed" name="cat_where" type="radio"><label for="cat_bed"> Bed</label> 
	<input id="cat_cushion" name="cat_where" type="radio"><label for="cat_cushion"> Cushion</label> 
</fieldset>