thanks for the info gents. I didn't know (or could not imagine, is more accurate) that there was a long-time, multi-browser, agreed-upon cross-platform industry standard in the the html language of colors, but I guess there would have to be the more I think about it....browsers (mostly) are agnostic to specific operating systems and just have to perform and be somewhat customizable, I imagine. Thanks again. edit: word addition
In case you experience crackling sound when streaming video/audio, for example YouTube, try setting media.webspeech.synth.enabled to false
To decrease or increase the size of the firefox interface, it will also change the zoom of the web pages (we will need to adjust it via the preferences to find the right balance between the zoom of the interface and the web pages), go to layout.css.devPixelsPerPx
1.2 will increase the interface to 120% for example, 0.8 will decrease it to 80%.
sangheeta To calculate it suitable for your DPI, I recall you can do simple math (your dpi) / 96
Security/Privacy related tweaks for firefox:
website mentioned is https://privacytools.io
https://privacytools.io/browsers/#about_config
important note: some of the tweaks listed in that website could cause you to lose some performance.However, you gain improved security as well as privacy for that sacrifice.
hope you find this useful 
For some extra protection you should activate the "Site Isolation" feature in Firefox, called Fission.
https://blog.mozilla.org/security/2021/05/18/introducing-site-isolation-in-firefox/
Re enabling the compact UI on latest Firefox:
browser.compactmode.show to true in about:config
Just leaving this here.
https://github.com/black7375/Firefox-UI-Fix
Here's a catalogue of various CSS tweaks for Firefox someone made. At the moment I'm using the Technetium one.
Junglist Interesting, gotta take a look whether Lepton or Technetium looks better to me.
brent I use Plasma with SolusDark theme, so all dark gray for me.
sangheeta thanks for this 
browser.uidensity set to 1 decreases UI size a bit
A mouse gestures extension for FF and chromium that I like and use:
https://addons.mozilla.org/fr/firefox/addon/smartup/?utm_source=addons.mozilla.org&utm_medium=referral&utm_content=search
If the right button is chosen for gestures, double right click is available in extension settings to popup context menu
about:config
privacy.firstparty.isolate=true (false is default).
Been hearing so many good about the FPI (first party cookie isolate) feature that it makes (according to internet chatter) things like decentralyze (cdn safe injector) and much of UBO, and cookie-auo-delete irrelevant. We will see. Not sure I buy it outright. I like the first extension a lot.
Of course loading got faster when I 86'd some extensions. Everything is balance, I suppose. I don't think Mozilla likes to advertise it, but about:config is a decent place to manage cookies and privacy vs 6-7 extensions. I had 6-7 extensions and really think it's overkill.
There is actually not much use anymore for enabling the old FPI (outside of TOR browser maybe) with all the current isolation / blocking features Firefox has, especially containers and Enhanced Tracking Protection. And AFAIK FPI isn't seeing much improvement anymore (if at all) and disables all or most of the current isolation / blocking features.
You should be better off just setting Enhanced Tracking Protection to "strict", properly setting up which data to clear when Firefox gets closed and using uBlock Origin.
It will almost give you the same results (IIRC FPI still isolates a bit more currently) while using current isolation / blocking features but with a lot less breakage.
And if you wan to up it a notch you can use Multi Account Containers together with the extension Temporary Containers (in auto mode). But with the ongoing improvements to Enhanced Tracking Protection most privacy enhancements can now be gained without using Multi Account Containers, making them pretty much only useful for their core use case (which is being able to log into the same site with different logins at the same time using the same browser with different containers).
Here's some good info about Total Cookie Protection (which is part of Enhanced Tracking Protection):
https://github.com/mozilla/multi-account-containers/issues/1974
More info can be found in the release and feature announcements by Mozilla.
Also there is work being done deprecating the old FPI:
https://bugzilla.mozilla.org/show_bug.cgi?id=1649876
So at one one point enabling it (if the setting is still there) will most likely just enable the current protection features you can already enable from the normal settings menu.
[deleted] that's the debate, you are right. I have the 'strict' and FF allegedly containers these cookies (using containers as an adjective) anyways for seperation. Your points very valid and your explanation excellent----it still leads me to believe that many extensions are overkill.
I will read both those links right now, thanks for your great reply.
sangheeta browser.uidensity set to 1 decreases UI size a bit
wow the tabs look better(and cleaner) now! so thanks again
