I have not been in any conversation or seen any request ever for “accessibility” that includes designing for smaller or smallest client settings. This might be a feature in browsers, but in my experience and understanding it's not connected to more accessible interfaces.

WCAG 2.2 draft features the following note:

When using text without specifying the font size, the smallest font size used on major browsers for unspecified text would be a reasonable size to assume for the font. If a level 1 heading is rendered in 14pt bold or higher on major browsers, then it would be reasonable to assume it is large text. Relative scaling can be calculated from the default sizes in a similar fashion.

In my reading it is starting from default styles on browsers, not user overrides to the smaller side.
But as https://medium.com/@vamptvo/pixels-vs-ems-users-do-change-font-size-5cfb20831773 has shown, there's a miniscule group of users (0.17% in the tested set) that go for “small” settings, while not a single “smallest“/“tiny”.

Because of the whole mess of T130691 and using min-width/min-height in px as way around this (not sure if IE 11 would be continuing to be a blocker here, but also probably not worth the further research), I'd suggest as way out to put min-height on search input as well and not further optimize for “small” user setting visually.

Design systems team: Was this bug carried over to the Codex version? Since WVUI may be frozen might be worth either resolving this or updating it to be about Codex.

@Jdlrobson I can't reproduce this bug in Codex.

Hi @StevenSun I can reproduce this with the Codex patch and there still seems to be some kind of problem here (although it changes with Codex):

Before focus:

After focus:

I see .cdx-text-input__input has height 32px set.

So either Vector needs to also set height 32px for that input, or Codex needs to use em's to define.

We'll need to sync the rule .vector-search-box-vue .vector-search-box-input with the Codex one.

.cdx-text-input__input as it's now standing has a min-height set, not a height anymore.

That we've set min-height in px instead of ems or rems in OOUI days had to do with rendering issues with ems only in IEs.
For Codex we could rethink that logic and provide min-height in relative units too now with leveled up browser support.

It's a small trade-off between being hundred percent sure our rendering is great everywhere at 100% and enabling a small number of users to go below 100% as part of their personal preference.

After rethinking, from usability point of view this should be declined. See parent task T325788 for reasoning.