[h0l0cube]

Overall, it's much less noisy than pug, just by removing the parentheses and commas. But if the objective of this kind of markup is trying to minimize visual noise, removing redundant closing tags (which have inconsistent rules) would be an improvement.

The shorthand for classes/IDs seems like a good idea too, if there's a way to do it that improves readability (and seems less magical to the unfamiliar coder)

[mopires]

Also, if we remove closing markup, the only way to understand if a markup is closed woud be by checking if a new markup is open. That doesn`t seem efficient.

[h0l0cube]

I guess pug's whitespace sensitivity permits a way to quickly tell if a tag is closed.

I'm a fan of higher expressiveness/minimalism, so perhaps I'm just biased in my preference, but I also appreciate how it removes the need to know/care about the inconsistent closing tag semantics of html.

[mopires]

Shorthand definitions would be a good feature to be added, but it needs refinement. We need to think carefully about how to implement in a way that would fit gracefully with the syntax and with the developer experience.