Default css doesn't work on Angular 7

Hello! I'm trying to style the context-menu since the default style (at least the one from the demo or the starblitz) is not working
I tried with code the style in the `style.css`  and using the `[menuClass]` making sure i have the `<!doctype html>` in the `index.html` file

I'm using angular 7 and ngx-contextmenu@5.4.0

Thank you for your answer