Dark email body content
Dark theme works great except that the message body content is set to have a white background of "#fff". An easy fix is the following:
1.) Apply a CSS filter. "filter: invert(1)" to the element with attribute data-testid="message-content:body"
2.) Apply another CSS filter to images so they are not inverted. CSS selector img.
I tried it and it works but it's not permanent since I'm only modifying the styles using the browser's dev tools.
Please add this to the dark theme CSS.