You can easily make adisplay of Gmail dark mode
on your desktop by using the "Themes" menu. First,open Gmail on your PC, and click the gear icon in the top-right. Now,
click "Themes." You'll find "Dark" listed as the
first option to the right of the "Default" color scheme — it'll
likely just seem like a black box. Click it, and then click "Save."
Gmail will now be in dark mode on your desktop.