Secure Shell doesn't support padding around the window. if you inject with css, you're breaking hterm's algorithms. any reports of bad cursor position at that point are not a bug in hterm. we have
crbug.com/267654 to add a proper setting for a border around hterm if you want to start it.
the first half cursor you circled in the screenshot that's in the upper left corner is a graphical glitch bug in Chrome. it shows up on other sites too. there's no known workaround. Chrome/blink/whatever needs to be fixed instead. there is an open bug in
crbug.com somewhere for it, but i can't find it atm.
i'm sure the hyper guys had a number of hterm bugs/feature requests, but they never contacted us, so we had no idea what issues they were running into (or that they were even using hterm). they effectively forked the project and never contributed back.
otherwise i don't really understand what you're reporting or requesting with line-height. we lock the height down specifically so fonts with bad glyphs don't push text above or below the line, so there shouldn't be any problems with cursor tracking wrt vertical position (and i haven't heard of any such reports for a long time now).
i haven't looked at that specific font, but just because someone claims it's monospace doesn't mean it actually is. we've received a number of reports where "monospace" fonts have glyphs that are wider or narrower than the space it's supposed to be restricted to. we have a request to dynamically workaround such broken fonts, but in the meantime, it's easier to select a non-broken font.
-mike