Weird CSS @import errors

I wanna change font, which cannot work because of some weird error I see in console.

```space-style
@import url('https://fonts.googleapis.com/css2?family=Overpass+Mono:[email protected]&family=Overpass:ital,wght@0,100..900;1,100..900&display=swap');
```

In console I see:

Ruleset ignored due to bad selector.

The more times @import directives I use, the more times I see exactly the same message in the console. If I comment all the @imports out, the errors vanish.

All the time (with or without @imports) I also see the following JS error in the console that may be related (I don’t know, TBH, whether it is related to this particular issue or whether it is unrelated and therefor a separate one):

Source map error: Error: URL constructor:  is not a valid URL.
Stack in the worker:resolveSourceMapURL@resource://devtools/client/shared/source-map-loader/utils/fetchSourceMap.js:56:22
getOriginalURLs@resource://devtools/client/shared/source-map-loader/source-map.js:73:24
workerHandler/</<@resource://devtools/client/shared/worker-utils.js:115:52
workerHandler/<@resource://devtools/client/shared/worker-utils.js:113:13

Resource URL: about:srcdoc
Source Map URL: https://firefox-source-docs.mozilla.org/devtools-user/debugger/source_map_errors/

The Source Map URL points to some documentation with a scary 7 (!) years old issue stating some weird things.

I run SilverBullet on 192.168.255.1:23456 and there is HAProxy as HTTPS frontend with self-signed certificate. I managed to, because it was told somewhere that without HTTPS some functions may be limited (which is IMHO very ill). The HAProxy configuration is as simple as:

frontend silverbullet from local
  mode http
  bind [email protected]:34567 ssl alpn h2,http/1.1 crt server.pem name silverbullet
  use_backend silverbullet

backend silverbullet from local
  mode http
  server silverbullet 192.168.255.1:23456 check

I access it normally at the URL https://192.168.255.1:23456. I do not want to run SilverBullet on public IP. I have WireGuard tunnels to the host from everywhere (mobile, other computers) to access the private IP. Adding hostname to /etc/hosts won’t help, because I cannot do this on Android.

There was no such issue few weeks ago, I used @import in SB v1. I now use Firefox 137.0 (64-bit) if it matters.

The overall effect of whatever is causing the issue is that I can no longer use @import in CSS.

Any ideas how to work around this, please? Can somebody explain to me what’s going on?