Interfering styles in oxygen.css

[mlw-x]

Hi all,

does anyone know why oxygen.css (ver. 3.9) contains styles for "Custom HTML tag support" in front-end css and how to disable it?

Starting from line 996 in oxygen.css there is a small set of styles with elevated specificity through :is():

/* Custom HTML tag support */
:-webkit-any(li, div._important),
:is(li, div._important) {
  display: list-item;
}`
...

Specifically, i added 3rd-party stylesheet for a menu, but above oxygen's styles override the display property. I don't want to touch the stylesheet as I'm not maintaining it, so i wonder how to get rid of those styles.

Any help or explanation appreciated :)