On a Mac, the Firefox Browser can’t be used in a real fullscreen. This means: Even when you use the default fullscreen option with cmd+shift+f, the address bar and tabs remain visible. The internet says, this is a Firefox bug on MacOS.
The solution is to use UserChrome.css, a way to customize a modern Firefox Browser.
Four steps:
- Find your profile folder by typing
about:supportinto the address bar. There you can find the path. - Inside this folder, create a subfolder calles chrome and inside a file userChrome.css.
- Copy the following CSS code into userChrome.css:
#navigator-toolbox[inFullscreen] {
height: 0.5rem;
margin-bottom: -0.5rem;
opacity: 0;
overflow: hidden;
}
#navigator-toolbox[inFullscreen]:hover,
#navigator-toolbox[inFullscreen]:focus-within {
/*
* Add some padding between the navbar and the top screen edge
* to be more visible while the macOS hidden menu bar shows up.
* The macOS menubar will hide after a few seconds.
*/
padding-top: 1rem;
height: auto;
margin-bottom: 0rem;
opacity: 1;
overflow: visible;
}- Close and restart Firefox.
Links