its so frustrating getting this to work without interfering with other shortcuts, just put a button.

Dear CSS Reload add-on authors (and I mean authors of ALL add-ons of this type)!

You must, YOU ABSOLUTELY POSITIVELY MUST provide a non-keyboard UI to trigger CSS reloading. Having ONLY a keyboard shortcut will make your add-on UNUSABLE to those whose desktop environment intercepts this shortcut for something else!