Audit custom styles vs theme.json

[iandunn]

As we learn more about theme.json, I have the feeling that we'll notice areas where we've added custom CSS directly to the theme unnecessarily.

My impression is that theme.json should be able to remove the need for ~70% of the typical custom CSS, but I'm also skeptical that it works out that way in real life. It'd be awesome to be proven wrong, though.

This applies to the header/footer block as well.

[tellyworth]

@kellychoffman @beafialho might have some advice (or is this more a Theme Team thing?)

[iandunn]

These milestones are where we're tracking issues that are best for the design team:

• https://github.com/WordPress/wporg-news-2021/milestone/4
• https://github.com/WordPress/wporg-mu-plugins/milestone/3

...and these ones are best for the theme team:

• https://github.com/WordPress/wporg-news-2021/milestone/3
• https://github.com/WordPress/wporg-mu-plugins/milestone/1

[iandunn]

Related WordPress/gutenberg#38694

[iandunn]

Also https://make.wordpress.org/core/2022/04/13/core-styles-and-theme-customization-the-next-steps/