CSS Custom Property
A CSS custom property is a reusable CSS value, often called a CSS variable. It follows the cascade and can change by scope or theme.
Another example
A card gets its --surface and --text values from the light or dark theme that's active.
Main parts
- 01Foundation or token
- 02Applied component
- 03Visible state and rule
Use it when
Use custom properties for themes, design tokens, and values shared across CSS.
Do not use it when
Never store page content or every one-time number in global custom properties.
Name used in code
--token-name Before you ship
Check content order, shared design values, component consistency, contrast, zoom, and layout changes by screen size. Verify every theme, language, and state. If there is motion, offer an equal reduced-motion experience.
Outcome: Use or define CSS Custom Property to make the visual experience clear and easy to use. User context: A card gets its --surface and --text values from the light or dark theme that's active. Design concept to apply: CSS Custom Property. Why it fits: Use custom properties for themes, design tokens, and values shared across CSS. Do not use it when: Never store page content or every one-time number in global custom properties. Design requirements: Set the content order, shared design values, and reusable components. Define how the layout changes by screen size and state. Keep useful design choices separate from decoration. Inclusion and resilience: Check contrast, zoom, languages, themes, and reduced motion when needed. Do not use color or effects as the only way to show meaning. Acceptance criteria: The design stays clear on phones and desktops, at zoom, in every theme, and in all supported languages. Interactive states stay clear and consistent. Evidence and limits (evidence boundary): A formal document may still be a draft, release candidate, or final version. Check its status and browser or platform support. Unknowns to confirm: Brand limits, amount of content, supported themes and languages, target devices, and design-system rules.
Check this request
Review the current use of CSS Custom Property. Definition: A CSS custom property is a reusable CSS value, often called a CSS variable. It follows the cascade and can change by scope or theme. Release checks: Check content order, shared design values, component consistency, contrast, zoom, and layout changes by screen size. Verify every theme, language, and state. If there is motion, offer an equal reduced-motion experience. Before changing code, report the evidence you found, gaps, severity, and the smallest safe fix.