Audio block invisible for block themes when dark mode is enabled

[dcalhoun]

Description

The contents of an Audio block with set media are invisible when using a block theme and enabling dark mode.

Step-by-step reproduction instructions

1. Enable the device's dark mode.
2. Open the editor for a site using a block theme.
3. Add an Audio block.
4. Set the media for the block.

Expected behaviour

The block's audio file name and icon are visible.

Actual behaviour

The block's audio file name and icon are invisible.

Screenshots or screen recording (optional)

Classic Theme	Block Theme

WordPress information

• WordPress version: 6.3.1
• Gutenberg version: 16.6.0
• Are all plugins except Gutenberg deactivated? Yes
• Are you using a default theme (e.g. Twenty Twenty-One)? Twenty Twenty-Three

Device information

• Device: iPhone 13 mini
• Operating system: iOS 16.6.1
• WordPress app version: 23.2

[fluiddot]

I managed to reproduce this issue in version 23.8 for a specific case (reference):

1. Go to the browser and activate Byrne theme.
2. Edit the Theme style and go to Styles -> Colors.
3. Check that the Background color is white (i.e. #FFFFFF).
4. Go to the app and ensure that the device's light mode is active.
5. Create/open a post.
6. Add an Audio block.
7. Set the media for the block.
8. Observe that the text elements are not visible.

If I change the background color to any other color the solution incorporated in #55627 works.

Background color #FFFFFF	Background color #FFFFFE	Background color ##000000 (with text color set to white)

[SiobhyB]

@fluiddot, I believe this was fixed following the change in #56752, which aligns with the fact that Byrne is a universal theme using style variables.

Here's the before/after I'm seeing without and then with the changes from that PR:

Before	After

I'll go ahead to close this issue again, as I believe it's resolved, but let me know if you spot other issues!