Dark Mode / Mail

Hi folks, So as someone with low vision, my preference is for a dark background with light/white text. I love dark mode, and have found ways to make it work in most things I do, even Word now supports dark mode and makes documents appear with a dark background. But what I would like to know is can I do this in Mail? When I saw the Show with Dark Background option in the View menu I thought this would be the solution, but it doesn't seem to be. Most messages still have a white background. I know I can use Smart Invert, but I would like to know if this is an option in Dark Mode. I know Outlook does it so was hoping Mail would as its my preferred email app for personal email. Thanks!