In the previous Vivaldi the accent color was specified by the site. Is it not working with the latest version?
If it can't work, is there a way to make it do?
1.12.955.48 (Stable channel) (64-bit)
Should work just fine, make sure you have 'accent color from active page' activated in your theme settings.
I have it enabled. In the past, I had a change every time I went to the site. It's one of the colors specified by "accent color" or "highlight color" now. It's not a color according to the site as before.