Advanced Firefox themes engine

[ineedmypills]

Improve the theme engine and allow users to change and add more. Colors, shapes, icons, sounds, homepage, etc.

[Jon]

Thanks for submitting an idea to the Mozilla Connect community! Your idea is now open to votes (aka kudos) and comments.

[Jon]

Similar idea here: New themes preinstalled in the browser 

[WoodwardIII]

It would be really cool if we could have themes like an opera GX! That would be great!

[WoodwardIII]

It seems like the closest thing to this idea currently is Firefox CSS. [link] Honestly, if they would just officially add support for it (show it in the store), I would just use that.

[Suraj_Mishra]

I remember going through some bugzilla threads in which developers were concerned about the security aspects(which is really really huge and serious in this case) of this change. They are aware of this feature requests by the users. But they haven't reached a solution for this (yet?).

[Ponda]

I support some form of official support for CSS themes. It would be safer anyway if they were vetted than Mozilla than downloaded from random third-party websites.

[pbzin]

Background image should also be able to be changed without css, on Android too

[Agentvirtuel]

Hello

A similar discussion here https://connect.mozilla.org/t5/discussions/inquisitiveness/m-p/42556

userContent.css

@-moz-document url(about:home), url(about:newtab), url(about:privatebrowsing) {
    .click-target-container *, .top-sites-list * {
        color: #fff !important ;
        text-shadow: 2px 2px 2px #222 !important ;
    }

    body::before {
        content: "" ;
        z-index: -1 ;
        position: fixed ;
        top: 0 ;
        left: 0 ;
        background: #f9a no-repeat url(connectmozillaorg.png) center ;
        background-size: cover ;
        width: 100vw ;
        height: 100vh ;
    }
}