~ HOW CHECKBOX HACK WORKS ~

Imagine a checkbox with this id


   <input type="checkbox" id="
   
    this
   
   ">

Imagine a label, with the same specific ID ( this ) in for attribute

A label


   <label for="
   
    this
   
   "> A label </label>

When you click in a label, the checkbox with same ID ( this ) becomes "checked". Using :checked and CSS advanced selectors (~, +), you can style the element. Try:

Check the checkbox

When checked, div turns blue


   #this:checked ~ div {
   
    new background color
   
   }

And finally, it's only important that the checkbox is hidden. Label works "alone"! Result:

Check the checkbox

When checked, div turns blue and label turns grey

That's all! Use your creativity :-)