It’s because id selectors are more important @agate - aka, have a higher specificity. You can lean more about specificity here. You have two selectors (at least) trying to apply styles to that element, .move-right and input[type='radio'] - the input[type='radio'] is superseding the class selector, but not the id selector. Here’s a screen shot of me looking at the dev tools on your page:
The .move-right properties are crossed out because the other ones are more important. If you want to use the class, you need to be more specific - or, you can give a property a super high specificity like this:
That will override the other properties. Hopefully, this helps.