Move the label to the left side of the checkbox using css only

I have following code:

<div>
 <span>
  <input type="checkbox">
  <label>I want this to be on the left side</label>
 </span>
</div>

And I would like to move the label to the left side of the checkbox using css styles only, as I cannot change the HTML file because it is autogenerated. Any ideas please? :)