Targeting only Firefox with CSS

Question

Using conditional comments it is easy to target Internet Explorer with browser-specific CSS rules:

<!--[if IE 6]>
...include IE6-specific stylesheet here...
<![endif]-->

Sometimes it is the Gecko engine (Firefox) that misbehaves. What would be best way to target only Firefox with your CSS rules and not a single other browser? That is, not only should Internet Explorer ignore the Firefox-only rules, but also WebKit and Opera should.

Note: I'm looking for a 'clean' solution. Using a JavaScript browser sniffer to add a 'firefox' class to my HTML does not qualify as clean in my opinion. I would rather like to see something that depends on browser capabilities, much like conditional comments are only 'special' to IE…

Answer 1

A variation on your idea is to have a server-side USER-AGENT detector that will figure out what style sheet to attach to the page. This way you can have a firefox.css, ie.css, opera.css, etc.

You can accomplish a similar thing in Javascript itself, although you may not regard it as clean.

I have done a similar thing by having a default.css which includes all common styles and then specific style sheets are added to override, or enhance the defaults.

Answer 2

Updated(from @Antoine comment)

You can use @supports

@supports (-moz-appearance:none) {
    h1 { color:red; } 
}

<h1>This should be red in FF</h1>

More on @supports here

Answer 3

The only way to do this is via various CSS hacks, which will make your page much more likely to fail on the next browser updates. If anything, it will be LESS safe than using a js-browser sniffer.

Answer 4

OK, I've found it. This is probably the most clean and easy solution out there and does not rely on JavaScript being turned on.

@-moz-document url-prefix() {
  h1 {
    color: red;
  }
}

<h1>This should be red in FF</h1>

It's based on yet another Mozilla specific CSS extension. There's a whole list for these CSS extensions right here: Mozilla CSS Extensions.

Answer 5

Here is some browser hacks for targeting only the Firefox browser,

Using selector hacks.

_:-moz-tree-row(hover), .selector {}

JavaScript Hacks

var isFF = !!window.sidebar;

var isFF = 'MozAppearance' in document.documentElement.style;

var isFF = !!navigator.userAgent.match(/firefox/i);

Media Query Hacks

This is gonna work on, Firefox 3.6 and Later

@media screen and (-moz-images-in-menus:0) {}

If you need more information,Please visit browserhacks

Answer 6

Using -engine specific rules ensures effective browser targeting.

<style type="text/css">

    //Other browsers
    color : black;


    //Webkit (Chrome, Safari)
    @media screen and (-webkit-min-device-pixel-ratio:0) { 
        color:green;
    }

    //Firefox
    @media screen and (-moz-images-in-menus:0) {
        color:orange;
    }
</style>

//Internet Explorer
<!--[if IE]>
     <style type='text/css'>
        color:blue;
    </style>
<![endif]-->