I have several questions on this topic, but I'll limit to one: when I use the macro that lists blog posts for a space, it looks awful. For the "excerpt" option it ignores styles, and for "excerpt" or "full" if there's a video in the blog post it shows some markup.
That's fine if that's the default (well not fine at all, but bearable) if there's a way to customise the styling with CSS. But since the cloud version of Confluence doesn't have - say - user macros, how can this be done?