How Custom CSS Works in WordPress 7.0

The new feature is powered by the customCSS block support. It adds a Custom CSS input field to the Advanced panel of the block inspector. Users can write CSS declarations directly inside this field — no need to include selectors. Nested selectors can be applied using the & syntax, but HTML markup is prohibited.

What Developers and Agencies Need to Know No immediate action required: The feature is enabled by default for all blocks, except those opted out for technical reasons. Capability gating: Only users with the edit_css capability will see the Custom CSS panel. This aligns with permissions for the Customizer and Global Styles. Server-side rendering: Blocks using render_callback or render in block.json will have the class injected into their first HTML element. Opt-out availability: Developers maintaining blocks that should not support custom CSS can explicitly disable it in block.json. For site operators, this change simplifies customization workflows, reducing dependency on custom plugins or developer intervention. Agencies managing client sites will find it particularly useful for granular design adjustments without touching global styles.Developers can leverage the new block-level Custom CSS support in WordPress 7.0. — Photo: Pixabay / Pexels What To Do Site Operators: Test the new feature in staging environments to evaluate how it can streamline your workflows. Confirm editor permissions for staff who need access to custom CSS. Theme Developers: Verify your blocks and themes are compatible with the new CSS field. If a block must opt out, update its block.json. Plugin Developers: Ensure blocks with server-side rendering correctly support the injected class. Related NewsWordPress 7.0 Introduces Viewport-Based Block VisibilityWordPress 7.0 Enhances Dimensions Support for BlocksWordPress 7.0 Introduces Expanded Pattern Editing ModesSources

Make WordPress Core, 2026-03-15

Report Tag: custom css

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