I do like the indenting. My initial reaction to the background change is that things look a bit 'stark' now. Though I admit am conditioned by the way that GitHub and Slack do things -- I'm used to some sort of box denoting a code block.

Ultimately I don't feel particularly strongly, but I'd probably come down on the side of having more than just a font and indent change signifying that something is a piece of code. I'm not sure what your underlying reason for the change is, so it's a bit hard to suggest good alternatives.

The existing grey blocks are certainly a bit ugly. Would it help to prettify them a bit? Both GitHub and Slack have nice rounded corners on the code blocks. Slack uses just a thin grey border and leaves the background colour untouched. Could something like that work?

Thanks for the feedback. You and @rpendleton think alike.