css media query that targets firefox pc only

Question

I want to add a specific style to my page but only on firefox running on a pc. I use this code to target just mac but what would be the windows equivalent? and Is there a way to do it with just media querys not javascript?

var FF = !(window.mozInnerScreenX == null);

if(FF) {
    if(navigator.platform.indexOf('Mac')>=0)
         {
            // is a mac and on firefox
         }

Answer 1

Css hack for firefox

@-moz-document url-prefix() { 
  .cssSelector {
     font-size: 14px;
  }
}

Reference

Answer 2

MDN Mozilla CSS Extension you can read all possible CSS extensions for mozilla also you can check this answer