Change admin layout CSS ?

Hi, is possible to change administration layout css ? I try change any styles and if i put in on css and add !important nothing change. Thanks

rg90 please use the search. This existing discussion explains how to do it by registering a custom less file https://discuss.flarum.org/d/21490-custom-css-for-admin-area-or

I changed everything I needed, but I can't use a style to change one thing in the administration, and that is this line of the graph.

It might be nice if the administration styles could be changed directly via the dashboard or some simpler method, but I'm still glad that it works.

And any tip to change font color if user type bad url page ? There is a {
so this i cant use.

Thanks