If it's not rendering as intended across all browsers, I'd call that broken. If it renders as intended and just look bad, that's taste.
The overall layout is fairly odd & weird - but it's the same in Chrome & Firefox. There is one technical bug with the main body font-size - it uses some invalid syntax (should be invalid in both Chrome & Firefox) & Chrome seems to be accepting it (against spec). The rule:
font-size: clamp( 1.125rem, 1.125rem + (1.333rem - 1.125rem) * (100dvw - 24rem) / (80rem - 24rem), 1.333rem );
It's entirely possible I'm misreading the spec on clamp() but as far as I understood it, clamp() performs math on a bunch of comma separated fixed values, calc() handles arithmetic operators - this seems to be combining those without a calc invocation, but maybe I misread & overlooked clamp arithmetic operators. Firefox just says it's invalid, no detail on why.