How to understand if the dark theme is enabled on ios?

Question

iOS

I am typing a letter and it is necessary to determine whether the dark theme is enabled. It's just that the dark theme just removes all the white color. And the white background disappears and the text color becomes black.
How to understand which theme is included? Better on css because js (sort of) cannot be embedded in an email

Answer 1

the solution is beefree.io threw a design here and then exported it. gave out html with div and not with table but the letter was displayed the same everywhere and in all themes