I think Firefox 75 broke auto-hide.css

[LOuroboros]

Title.
In Firefox 75, possibly a product of the Megabar, the position of the navbar is off when using toolbars/auto-hide.css.
https://streamable.com/tze7ej

[ameerdevs]

Likewise here with 75 under linux

[A-Lamia]

Had the same problem, i came up with a quick fix not sure yet if there is a better way currently but it's working for now.

#urlbar { 
  position: absolute!important;  
  top: 0!important; 
} 

#urlbar-input-container {
  height: 32px!important;
}

The height value would change based on what you have yours set to.

[pauricthelodger]

Cheers for that, @A-Lamia!

With yours I got the following:

So I tweaked it a little bit more to this:

#urlbar { 
  position: absolute!important;  
  top: 3px!important; 
} 

#urlbar-input-container {
  height: 26px!important;
}

And got:

The tweaks might just be for my local though so ymmv =)

[A-Lamia]

Glad it helped @pauricthelodger.

That's why it's a quick fix, top and height need to be adjusted to fit your local firefox version, been looking in to a more static solution but the couple i have come up with had other side effects that are not desirable.

[A-Lamia]

So after some time i have figured out that the issue is the code is setting #urlbar's internal variable --urlbar-toolbar-height to 1px from 32px (or what ever yours is set to.).

The value of --urlbar-toolbar-height from what i can tell (could be wrong) is fetched from what ever the height of #nav-bar is on startup, in this case it gets set to 1px because of auto hide.

This is causing a calc() function on the top property in #urlbar[breakout] to calculate incorrectly giving us the positioning errors.

#nav-bar {
        --navbar-height: 32px;
 }

 #nav-bar:not([customizing="true"]):not([inFullscreen]){
	min-height: 1px !important;
	max-height: 0px !important;
	margin-top: 1px !important;
  	margin-bottom: -1px !important;
	transition: all 50ms linear 0s !important;
	z-index: -5 !important;
}

#navigator-toolbox:hover:not([inFullscreen]) :-moz-any(#nav-bar),
#navigator-toolbox:focus-within :-moz-any(#nav-bar) {
        min-height: var(--navbar-height) !important;
	max-height: var(--navbar-height) !important;
	margin-top: 1px !important;
  	margin-bottom: calc(-1 * var(--navbar-height)) !important;
  	opacity: 1 !important;
  	transition: all 50ms linear 0s !important;
	z-index: 5 !important;
}

/* Restores the variables original value. */
#urlbar.megabar {
        --urlbar-toolbar-height: var(--navbar-height) !important;
}


/* Positions the url view to the bottom of your toolbar and aligned with top border. */
.urlbarView.megabar {
        top: -2px !important;
}

[Glandos]

See #175
I chose not to use another variable to make things simple.

[LOuroboros]

Since right now auto-hide.css no longer hides the bookmarks bar forcing the user to add a separate piece of code (sliding-bookmarks-bar.css), I looked into fixing the old code for auto-hide.css when it still contained the bits that hid the bookmarks bar on the process for my personal use, and thanks to the modification provided above by @A-Lamia, I was able to.
Thank you very much, A-Lamia!

This is how it looks on my end:

/*
 * Auto-hide the URL-bar and bookmarks bar, show on hover or focus
 * https://github.com/Timvde/UserChrome-Tweaks/blob/master/toolbars/auto-hide.css
 * Contributor(s): Alex Vallat
 */
 
#PersonalToolbar:not([customizing]),
#nav-bar:not([customizing="true"]):not([inFullscreen]) {
    min-height: 1px !important;
    max-height: 0px !important;
    margin-top: 1px !important;
    margin-bottom: -1px !important;
    transition: 0s !important;
    z-index: -5 !important;
}
 
#navigator-toolbox:hover:not([inFullscreen]) :-moz-any(#nav-bar),
#navigator-toolbox:focus-within :-moz-any(#nav-bar) {
    min-height: 30px !important;
    max-height: 30px !important;
    margin-top: 1px !important;
    margin-bottom: -30px !important;
    transition: 0s !important;
    z-index: 5 !important;
}
 
#navigator-toolbox:hover:not([inFullscreen]) :-moz-any(#PersonalToolbar),
#navigator-toolbox:focus-within :-moz-any(#PersonalToolbar) {
    min-height: 21px !important;
    max-height: 21px !important;
    margin-top: 30px !important;
    transition: 0s !important;
    z-index: 5 !important;
}

#urlbar { 
  top: 4px !important;
  bottom: 0px !important;
}

[Timvde]

I would very much welcome a pull request :)