

Themes can add/override these styles, or they can provide no styles at all, and rely fully on what the blocks provide. They also provide opt-in opinionated styles.

Frontend & Editor Styles – To get the most out of blocks, theme authors will want to make sure Core styles look good and opt-in, or write their own styles to best fit their theme.Responsive Embeds – Themes must opt-in to responsive embeds.Editor Text Size Palette – A default set of sizes is provided, but themes can register their own and optionally lock users into picking from preselected sizes.Editor Color Palette – A default set of colors is provided, but themes can register their own and optionally lock users into picking from the defined palette.

There are a few new concepts to consider when building themes: The new Blocks include baseline support in all themes, enhancements to opt-in to and the ability to extend and customize. Browse: Home / Block Editor Handbook / How-to Guides / Themes / Theme Support Theme Support Edit
