Pseudo-element
A pseudo-element lets CSS style a part or box with no normal element in the source HTML. Examples include the first letter and generated decoration.
Another example
An article uses `::first-letter` for a decorative drop cap and `::selection` to keep selected text readable. A required-field star is not made with `::before` alone. “Required” is still visible in the legend and available to software if color or generated content is missing.
Main parts
- 01Originating element
- 02Pseudo-element tree abstraction
- 03Generated or selected fragment
Use it when
Use pseudo-elements for optional decoration or a defined text part. Add no empty DOM element when it gives no meaning.
Do not use it when
Do not put required instructions, working controls, or the only accessible label in generated content.
Name used in code
::before, ::after, ::marker, ::selection, ::first-letter 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 Pseudo-element to make the visual experience clear and easy to use. User context: An article uses `::first-letter` for a decorative drop cap and `::selection` to keep selected text readable. A required-field star is not made with `::before` alone. “Required” is still visible in the legend and available to software if color or generated content is missing. Design concept to apply: Pseudo-element. Why it fits: Use pseudo-elements for optional decoration or a defined text part. Add no empty DOM element when it gives no meaning. Do not use it when: Do not put required instructions, working controls, or the only accessible label in generated content. 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 Pseudo-element. Definition: A pseudo-element lets CSS style a part or box with no normal element in the source HTML. Examples include the first letter and generated decoration. 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.