CSS from quick css and child theme styles.css are ignored

Hi,

I’m running into a strange issue with css edits – sometimes neither quick css nor styles.css from my child theme take any effects, changing the original css file does work as expected (but obviously might be overwritten with an update). Could you give me a hint on how to troubleshoot this?

Specifically I wanted to reformat the avia element Symbolliste. Adding this to quick css or styles.css did nothing:

.avia-icon-list .iconlist_title {
padding-bottom: 20px;
padding-left: 10px
}

but changing it in the iconlist.css worked as expected.

Any hints welcome,
Thanks