Google Chrome does not load custom Stylesheet/CSS - but Firefox OK

Configuration
1

I’ve defined a custom CSS file in “ui-lovelace.yaml”

        - url: /local/my-webfont.css
           type: css

but that stylesheet works only in FF, but not in Chrome.
Screenshot FF:

css-FF
css-FF731×165 6.71 KB

Screenshot Chrome:

css-chrome
css-chrome755×151 3.46 KB

Additionally, even the “Stylish Addon” doesn’t work in Chrome for the hass webpages, but does for any other web-page.

Any ideas?
thanks in advance