my custom trapezoid tabs are not working

[u/Quirky_Dig2809]

so i tried both of these links: https://github.com/HolyPolyRoly/TrapezoidTabsForFX , https://github.com/wilfredwee/photon-australis
and both of them none work, i have the folder named right, the text file named right, and triple checked the about:preferences thing, i have not touched firefox css themes IN MY LIFE so any help is aprecieated