- open firefox
- goto
about:config - set
toolkit.legacyUserProfileCustomizations.stylesheetstotrue
find the Profile Directory path on about:support
- create a new directory named
chromeinside<profile-directory> - inside
chromedirectory, create 2 filesuserChrome.cssuserContent.css
add css below to userChrome.css
.titlebar-buttonbox-container,
.titlebar-spacer {
display: none;
}