In Tor Browser, “noir mode” is usually just the Dark theme. Open the browser’s menu, go to Settings or Extensions & Themes, then under Themes select Light or System instead of Dark.

Quick steps

  1. Open Tor Browser.
  2. Open the menu in the top-right.
  3. Go to Settings.
  4. Open Extensions & Themes.
  5. Choose Themes.
  6. Click Enable on Light or System.

If websites still look dark

Some sites follow their own dark-mode setting, separate from the browser theme. If a site still appears dark after switching Tor Browser to Light or System, change that site’s own appearance setting in its page menu or account settings.

Note

Tor Browser versions since the newer theme setup use the add-ons/themes area for appearance changes, so the old wording may not match exactly depending on your version.

TL;DR: turn off Dark in Tor Browser’s Themes and switch to Light or System.