JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox" id="check" checked /><br />
#<input type="text" size="8" maxlength="6" id="colour" placeholder="ffffff" />

<script>
    $('#check').change(function(){
        if( $('#check:checked') ){
            $('#colour').removeAttr('disabled');
        } else {
            $('#colour').attr('disabled','');
        }
    });
</script>

CSS

</style>
<script type="text/javascript" src="//code.jquery.com/jquery-1.10.2.min.js"></script>
<style>
input[type=checkbox] {
    -ms-transform: scale(1.5);
    -moz-transform: scale(1.5);
    -webkit-transform: scale(1.5);
    -o-transform: scale(1.5);
}