I agree with you 100%; I hate it when websites think they’re being trendy by using undraggably-thin scrollbars or try to subvert the UA’s password-manager (bank

I agree with you 100%; I hate it when websites think they’re being trendy by using undraggably-thin scrollbars or try to subvert the UA’s password-manager (banks…) or naively think they can block users right-clicking or copying images. To clarify my position: I agree that UAs should be free to show validation messages as-appropriate for the user (I.e. those popover hints) but it is because Google decided to stylise them with a very specific aesthetic/design - as opposed to trying to fit-in to the host system - it clashes more. Now, I’m not suggesting that the UA popovers be fully CSS-able, but I would like to see some kind of coarse-grain control “hint” properties - just like we have with (non-WebKit-prefixed) scrollbars, <button>, most <input> types, and more besides. The issue here is that the validation popovers are almost uniquely exempt from styling compared to all other HTML platform features (the only other exception being `title=“”` tooltips, AFAIK). By-comparison, this is kinda like the (still) half-broken support for dark-mode: if a page is dark-themed you (probably) don’t want nuclear-flash-white UA-provided popovers stinging your eyes because there’s no validation-popover background color hint. Similarly, supposing my website makes tasteful use of serif typefaces - but the input validation popovers will be in Chrome’s own Material-design sans-serif font, while OS/platform widgets will be in some third other font by-default but can generally still be set via CSS. If you’re on HN then you’re likely bothered by inappropriate mixing of serif and sans-serif typefaces, so I hope you can sympathise.