I’m using arc theme (Darker variant), and I noticed that the theme used in desktop and websites, differs. I don’t know if this is normal:
Website (System lnf)
It may sound little stupid, but I think it’s theming problem because that doesn’t occurs with Pocillo. And I don’t see the strange ugly gnome default style hanging around, even on apps (I’ve used) using system lnf.
Strangely QogirBudgie also has the very same issue.
I think that websites (Which used the default system lnf) are using the default gnome look and feel slightly.