MD (and MDX) source code blocks to be dark

[csantos1113]

This is a styling question, but first, the context:

When you do something like: <Source code="const HI = 'hello';" dark />
You can explicitly indicate that you want that source code to use the dark colors:

Question:

Is there a way to force blocks of code (```) that are written in MDX or MD files to be dark? right now those code blocks are white.