EDIT 2021-Aug-11: FireFox 91 changed something, this no longer works 😠😡😠😡😠😡. Please see https://support.mozilla.org/en-US/questions/1339768#answer-1434053
Problem: new Firefox tabs look horrible and do not stand out as visible tabs.
about:config > browser.
proton.
enabled > false (no longer works in FF-91)
Fixed.
NEW SOLUTION:
1) Create a new folder/file in your user profile as
chrome/userChrome.cssand fill it with contents (generated from your selected preferences) from this link: https://www.userchrome.org/firefox-89-styling-proton-ui.html#tabstyler
2) set
toolkit.legacyUserProfileCustomizations.stylesheets as
true via
about:config .
3) restart FireFox.
example result: (https://sharetext.me/heyafkro)
SEO:
Fix FireFox 89, 90, 91 Tabs Look
Fix FireFox 89, 90, 91 Tabs Look and Feel
Fix Firefox Tabs
Fix FireFox Proton Tabs
Revert Firefox Tabs
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