Details Block: allow the option to choose from a set of icons

[annezazu]

This was raised as part of the FSE Outreach Program's Rapid Revamp call for testing:

A small suggestion for the details block: could we have a set of icons to choose from, like “+” and “v”? And an option to place the icon after the text?

This could perhaps reuse what we have in place for the navigation block:

[hanneslsm]

This could perhaps reuse what we have in place for the navigation block:

I think it makes sense to think about something that could be used in multiple areas, such as the cosmic list types: #45830

[justintadlock]

I'm OK with some marker options, but I'd rather see them happen through the block styles API than as a specific block attribute with a custom control. This is because it creates poor UX when theme authors add block styles that change the marker but the core UI shows a different marker.

[richtabor]

It's a typographic figure, and not easily manipulated (can get complicated and is non-standard).

I don't see this happening in core.

[davewhitley]

I find the lack of customization options to be very limiting in my experience building sites with the site editor. Would it be more pragmatic to create a whole new accordion block instead of expanding the details block? What are the hurdles for creating a new accordion block that would allow more customization options?

Adding some better options (other than the default ones) for background color and borders would be a big improvement (example).

It looks like Safari will not be able to style ::marker any time soon, unfortunately. What is stopping us from removing the marker and implementing custom ones via background? (example)

or use ::after

[richtabor]

What is stopping us from removing the marker and implementing custom ones via background? (example)

The SVGs would have to be linked via CSS, which isn't ideal.

[jarekmorawski]

FWIW, I put together a mockup a while back for what more advanced settings in the details block could look like. I think this work could be unlocked if we build an Icon block that supports icon fonts or sanitized SVGs (or both).