Appearance settings for Safari 15 menu bar

CORRECTION TO THE POST BELOW:

The issue is NOT Dark Mode on Safari 15, but is instead the menu bar at the top of the app window mimicking whatever color is at the top of the web page. For example, on this Apple site, the entire menu bar turns black because of the blank menu band at the top of this page.

Is there a way to turn of this particular feature?

Original Post:

Is there a way to manually turn off Dark Mode for the new Safari 15? It defaults to Dark Mode, even though I've turned it off completely using Appearance under General in System Preferences.

I can't find a way to switch it off in Safari settings.

TIA