Editor: Backport foundation for Layout block support refactor (part 1).
This change backports the following changes from Gutenberg repository:
- [WordPress/gutenberg#40875 gutenberg#40875] Layout: Use semantic classnames, centralize layout definitions, reduce duplication, and fix blockGap in theme.json
- [WordPress/gutenberg#42544 gutenberg#42544] Layout: Add a disable-layout-styles theme supports flag to opt out of all layout styles gutenberg#42544
- [WordPress/gutenberg#42087 gutenberg#42087] Theme.json: Add block support feature level selectors for blocks gutenberg#42087
- [WordPress/gutenberg#43792 gutenberg#43792] Global Styles: Split root layout rules into a different function gutenberg#43792
- [WordPress/gutenberg#42544 gutenberg#42544] Layout: Add a disable-layout-styles theme supports flag to opt out of all layout styles gutenberg#42544
- [WordPress/gutenberg#42665 gutenberg#42665] Layout: Reduce specificity of fallback blockGap styles gutenberg#42665
- [WordPress/gutenberg#42085 gutenberg#42085] Core CSS support for root padding and alignfull blocks gutenberg#42085
Note that it doesn't entirely port over PR40875 — the remaining PHP changes for that PR will be explored in a separate PR targeting layout.php
.
Props andrewserong, aaronrobertshaw, isabel_brison.
See #56467.