I am testing on my Asus tablet running Android 4.3. (Link to specs on tablet below). Here is the only query: @media only screen and (device-aspect-ratio: 16/10) Chrome and Opera will load and apply the styles perfectly, but Firefox loads nothing. BTW, if I change the query to: @media only screen and (min-device-width: 1000px) the styles apply just fine, but I wish styles would load via the aspect-ratio query just like Chrome and Opera. Also, one thing that's kind of wierd, but I don't think (??) has any bearing on this issue is this . . . but it may. The specs on my tablet say it has a 1920 x 1200 screen resolution, but when I go to different websites that detect your screen res, they report back 1280 x 800. I have tried numerous ways to express device-pixel-ratio, but nothing has worked. For example, I tried: -webkit-min-device-pixel-ratio: 1.5 . . . as well as many others. Perhaps I've just not hit on the exact expression I need. (??) I think I tried all your suggestions here: https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Media_queries#-moz-device-pixel-ratio Thanks for any help or advice you may be able to give me on this. I really like using this version of FF on my tablet. Seems to run very "snappy." I like many of the features as well. Just kind of puzzled by this one issue with regard to this little webpage of my own I'm working on. I'm attempting to load a background image based on the device's aspect ratio. http://www.asus.com/us/Tablets_Mobile/ASUS_MeMO_Pad_FHD_10_ME302C/specifications/