2nd/10_Wiki/Dev/Topic_HOWTO/HOWTO_CSS_Mixed_Columns.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
howto-css-mixed-columns	How To - Mixed Column Layout	Web_Recipes	draft	conceptual		responsive 4-2-1 column layout		B	0.83	2026-07-04	2026-07-04			howto css w3schools layout float responsive media-queries	https://www.w3schools.com/howto/howto_css_mixed_columns.asp

HOWTO CSS Mixed Columns

🎯 한 줄 통찰 (One-line insight)

Where [[HOWTO CSS Four Columns]] collapsed directly from 4 columns to 1 stacked column at a single breakpoint, this recipe adds an INTERMEDIATE step — two STACKED media queries (900px, then 600px) progressively widen each column's percentage (25% → 50% → 100%) as the screen narrows, demonstrating that responsive breakpoints aren't limited to one "desktop vs. mobile" cutoff; they can chain to create a 4-column → 2-column → 1-column cascade, with each @media rule simply overriding the previous width at a narrower threshold. [S1]

🧠 핵심 개념 (Core concepts)

• Base layout: 4 equal float columns — .column { float: left; width: 25%; } plus the standard .row:after clearfix. [S1]
• First breakpoint (900px): 4 → 2 columns — @media (max-width: 900px) { .column { width: 50%; } }. [S1]
• Second breakpoint (600px): 2 → 1 column — @media (max-width: 600px) { .column { width: 100%; } }. [S1]
• Cascading override order matters — later (narrower) media queries must come after earlier (wider) ones in the stylesheet so they correctly override at smaller widths, per normal CSS cascade rules. [S1]

📖 세부 내용 (Details)

• Full progressive layout: .column { float: left; width: 25%; } .row:after { content: ""; display: table; clear: both; } @media screen and (max-width: 900px) { .column { width: 50%; } } @media screen and (max-width: 600px) { .column { width: 100%; } }. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• 단일 브레이크포인트가 아니라 다단계 캐스케이드: [[HOWTO CSS Four Columns]]는 600px 하나의 브레이크포인트로 4열→1열로 바로 붕괴시켰지만, 이 레시피는 900px(4→2열)과 600px(2→1열) 두 단계를 거치는 점진적 붕괴를 사용한다는 점이 확인됨 — 반응형 브레이크포인트가 여러 단계로 연쇄될 수 있음을 보여줌. [S1]

🛠️ 적용 사례 (Applied in summary)

화면 폭에 따라 4열→2열→1열로 점진적으로 바뀌는 컬럼 레이아웃 예제가 원문에서 직접 제시됨. [S1]

💻 코드 패턴 (Code patterns)

Progressive breakpoint cascade — 4 columns → 2 → 1 (CSS):

.column { float: left; width: 25%; }

@media screen and (max-width: 900px) {
  .column { width: 50%; }
}
@media screen and (max-width: 600px) {
  .column { width: 100%; }
}

✅ 검증 상태 및 신뢰도

• 상태: draft
• 검증 단계: conceptual
• 출처 신뢰도: B (W3Schools — widely used educational reference)
• 신뢰 점수: 0.83
• 중복 검사 결과: 신규 생성 (New discovery)

🔗 지식 그래프 (Knowledge Graph)

• 상위/루트: W3Schools HOW TO
• 관련 개념: HOWTO CSS Four Columns, HOWTO CSS Responsive Floats, HOWTO CSS Two Columns
• 참조 맥락: CSS Layout & Positioning 섹션.

📚 출처 (Sources)

• [S1] W3Schools — How To - Mixed Column Layout — https://www.w3schools.com/howto/howto_css_mixed_columns.asp

📝 변경 이력 (Change history)

• 2026-07-04: Initial draft synthesized from the W3Schools "How To - Mixed Column Layout" recipe (Astra wiki-curation, P-Reinforce v3.1 format).