2nd/10_Wiki/Topic_CSS/CSS_Pseudo_Classes.md

id, title, category, status, verification_status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, created_at, updated_at, review_reason, merge_history, tags, raw_sources, applied_in, github_commit

id	title	category	status	verification_status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	created_at	updated_at	review_reason	merge_history	tags	raw_sources	applied_in	github_commit
css-pseudo-classes	CSS Pseudo-classes	Frontend	draft	conceptual		pseudo-classes pseudo class special state styling hover focus active structural pseudo-classes		B	0.85	2026-06-23	2026-06-23			css web frontend w3schools selectors pseudo-classes	https://www.w3schools.com/css/css_pseudo_classes.asp

CSS Pseudo-classes

🎯 한 줄 통찰 (One-line insight)

A CSS pseudo-class is a keyword added to a selector to define a style for a special state of an element — such as hover, focus, visited links, or position within the document tree. [S1]

🧠 핵심 개념 (Core concepts)

• Definition — a CSS pseudo-class is a keyword that can be added to a selector, to define a style for a special state of an element. [S1]
• Syntax — a single colon followed by the pseudo-class name, attached to a selector. [S1]
• Common use cases — styling on mouse hover, distinguishing visited vs unvisited links, focus states, and form validation states. [S1]
• Interactive pseudo-classes — respond to user actions: :hover, :focus, :active, :link, :visited. [S1]
• Structural pseudo-classes — select based on document-tree position: :first-child, :last-child, :nth-child(n), :lang(). [S1]

🧩 추출된 패턴 (Extracted patterns)

• State-based styling — append :state to a selector to style a transient or contextual condition rather than a static element. [S1]
• Two families — interactive (user-driven) vs structural (position-driven) pseudo-classes cover the two broad selection needs. [S1]

📖 세부 내용 (Details)

What is a pseudo-class? A CSS pseudo-class is a keyword that can be added to a selector, to define a style for a special state of an element. [S1]

Syntax [S1]

selector:pseudo-class-name {
  CSS properties
}

Common use cases The page identifies common applications including styling on mouse hover, distinguishing visited versus unvisited links, focus states, and form validation states. [S1]

Interactive pseudo-classes (respond to user actions) [S1]

• :hover — when the mouse is over an element.
• :focus — when an element has focus.
• :active — when an element is being activated.
• :link — unvisited links.
• :visited — visited links.

Structural pseudo-classes (select by document-tree position) [S1]

• :first-child — first child of a parent.
• :last-child — last child of a parent.
• :nth-child(n) — the nth child of a parent.
• :lang() — elements with a specific language.

All CSS Pseudo-classes (reference table) Not found in source — the tutorial page links to the separate "CSS Pseudo-classes Reference" for the complete list rather than embedding the full table. [S1]

🛠️ 적용 사례 (Applied in summary)

The page describes (rather than ships full code for) common applications: hover styling, visited/unvisited link distinction, focus states, and form-validation states. Detailed worked examples live on the linked interactive and structural pseudo-class pages. No external project/commit applications found in the source.

💻 코드 패턴 (Code patterns)

General pseudo-class syntax (language: CSS):

selector:pseudo-class-name {
  CSS properties
}

⚖️ 비교 및 선택 기준 (Comparison & decision criteria)

• Interactive vs structural — choose an interactive pseudo-class (:hover, :focus, :active, :link, :visited) to react to user actions or link state; choose a structural pseudo-class (:first-child, :last-child, :nth-child(n), :lang()) to select by position in the document tree. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

No contradictions found in the source.

✅ 검증 상태 및 신뢰도

• 상태: draft
• 검증 단계: conceptual (실제 적용 사례 발견 시 applied/validated로 승격 가능)
• 출처 신뢰도: B (W3Schools — widely used educational reference, not a primary standards body)
• 신뢰 점수: 0.85
• 중복 검사 결과: 신규 생성 (New discovery)

🔗 지식 그래프 (Knowledge Graph)

• 상위/루트: CSS Tutorial
• 관련 개념: CSS Interactive Pseudo-classes, CSS Combinators, CSS Selectors, CSS Pseudo-elements
• 참조 맥락: The entry point for styling special element states (hover/focus/link) and structural positions.

📚 출처 (Sources)

• [S1] W3Schools — CSS Pseudo-classes — https://www.w3schools.com/css/css_pseudo_classes.asp

📝 변경 이력 (Change history)

• 2026-06-23: Initial draft synthesized from the W3Schools "CSS Pseudo-classes" page (Astra wiki-curation, P-Reinforce v3.1 format).