[Following on from a user report at enWS]
If the browser font size is set to smaller than default (16), the layout of an OOUI FieldLayout is incorrect. For example, editing any index page at enWS should look like this:
But if you set a font size of 15 or lower, it looks like this:
I imagine it's related to this CSS:
.oo-ui-fieldLayout.oo-ui-labelElement.oo-ui-fieldLayout-align-left > .oo-ui-fieldLayout-body > .oo-ui-fieldLayout-help, .oo-ui-fieldLayout.oo-ui-labelElement.oo-ui-fieldLayout-align-right > .oo-ui-fieldLayout-body > .oo-ui-fieldLayout-help { margin-right: 0; margin-left: -2.35714286em; }
Changing that to -3em, for example, seems to work.
The report was in Chrome, and I reproduced in Firefox.