Dynamic background is transparent when the cover is Navidrome's default fallback cover image

[OriginCode]

Expected Behavior

A blue or fallback color should be used.

Current Behavior

Steps to Reproduce

1. Play a song with no cover image, which Navidrome will provide a fallback image instead.

Possible Solution (Not obligatory)

Add a fallback background color?

Context

It doesn't look right, as you can see the content below the now-playing interface.

Your Environment

• Application version (e.g. v0.1.0) : v0.3.0
• Operating System and version (e.g. Windows 10) : Windows 11 (as far as I know this also happens in Linux (AOSC OS 10))
• Server and version (e.g. Navidrome v0.48.0) : Navidrome 0.49.3
• Node version (if developing locally) : N/A

[jeffvli]

Fixed in latest development versions