Css media request designed for firefox pc only

Question

I want to add a specific style to my page, but only on firefox running on the computer. I use this code for targeting only for Mac, but what will be the equivalent of Windows? and is there a way to do this using only media queries, 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 firefox

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

Link

Answer 2

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