How to add Css into Resource file??

Question

Hj all. I have just create a resource file for a button.When I choose English or French ,so the button change Text. And i want to add Css into resource file to display different style when i choose English or French language.I mean when i choose English ->My button like this:
#Button1

{

    color:Red;

    width:100px;

    height:100px;

} 
and when i choose French the button like this:

#Button1

{

    color:Blue;

    width:200px;

    height:200px;

}
Someone help me for that!
Thanks.