A reader in OTRS #2018101910000341 reports that image captions overlap with other article text when viewed on IE11 on Windows Phone 8.1:
{F26687204}
(image and version details shared with permission)
= Developer notes
Visit https://en.m.wikipedia.org/wiki/Igneous_rock on IE11 Windows 10
== Fixing the gray background
IE11 doesn't fully support HTML5.
The issue here is the `main` tag is not recognised by IE11 and needs display: block.
Documented here: https://weblog.west-wind.com/posts/2015/Jan/12/main-HTML5-Tag-not-working-in-Internet-Explorer-91011
Fix: Add display block to main elements in the "reset"
== Fixing overlapping thumbnails
IE11 has buggy support for display flex.
Wrap the display: flex rules inside a feature query. https://caniuse.com/#search=feature%20queries (IE11 does not support feature queries). Display flex is not essential for these rules.