hm. so possibly what i thought was a bug in cohost's pwa may actually be an issue in firefox*
* Whenever i open the pwa it looks like there's a space for the address bar but it's just blank, and the whole site starts ~75px (bad eyeballing, pixel ratios confuse me) down or so
can confirm.
it may be worth mentioning that the space at the top is the system status bar. date/time, battery charge, etc. at least on my phone.