Debugging

Fast checks:

1. Confirm you edited the active theme (Site Editor → theme).
2. Check if user customizations exist (they override theme defaults).
3. Validate theme.json structure (typos can prevent styles from applying).
4. If a var(--wp--preset--*) / var(--wp--custom--*) reference is silently using its fallback, the slug is likely un-normalised — WordPress hyphenates digit/letter boundaries and camelCase transitions before emitting the CSS var. See theme-json.md § “Slug normalisation gotcha”.

Remember the hierarchy:

• core defaults → theme.json → child theme → user customizations

Templates/parts not showing

• Ensure files are in the correct folders (templates/, parts/).
• Template parts must not be nested in subdirectories.

Style variations not updating

• If a user already selected the variation, the selection is stored in the DB.
• Test with a fresh site/user or reset customizations when appropriate.