Nextcloud white header -> invert app icons in internet explorer 11


i themed my nc 12.0.3 (custom theme, no theme app) with a white header, but in ie11 the app-icons won’t be invertet to dark color.
Afaik this inverting of the icons are realized over css filters:

#appmenu li a img {
-webkit-filter: invert(1);
filter: invert(1);
filter: progid:DXImageTransform.Microsoft.BasicImage(invert=‘1’);

Google says, that Microsoft stopt the support of the css-filter in ie10. Does anyone know how to fix the problem in a conventional way?