Line 39: @media (-moz-bool-pref: "userchrome.vertical-tabs.on-right.enabled"){
This line doesn't work for me, even though I have set that preference. If I comment out this line (and its closing brace), then the code block does work correctly--it just doesn't recognize the preference. Could it be because I'm testing on FF 115 ESR?
In multi-row_tabs_below_content.css (a commit from June) this line:
Line 239: @supports -moz-bool-pref("userchrome.multirowtabs.static-menubar.enabled"){
and its code block do work correctly for me.
Back to vertical_tabs.css, I tried using @supports instead of @media, and that did work.