(Hopefully) finally fixed the issue causing the first reply button element to gain the "Join" button's styling.
Adjusted Join button's gradient to resemble 2008 YouTube a bit better while still looking good on dark or light theme, and changed color of the "Join" text to match 2008 YouTube.
Like count text in comments are now coloured green to match the like buttons, and the "reply" text in the reply button is styled to look like 2008 YouTube.
(Minor code clean-up & adjustments.)