2nd/10_Wiki/Dev/Topic_W3CSS/W3CSS_Rows.md

---
id: w3css-rows
title: "W3CSS Rows"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["w3-row", "w3-half", "w3-rest", "W3.CSS 행 시스템"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.88
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["w3css", "css-framework", "w3schools", "rows", "responsive-grid"]
raw_sources: ["https://www.w3schools.com/w3css/w3css_rows.asp"]
applied_in: []
github_commit: ""
---

# [[W3CSS Rows]]

## 🎯 한 줄 통찰 (One-line insight)
Every named-fraction column class (`w3-half`, `w3-third`, `w3-quarter`, etc.) automatically collapses to 100% width below 601px — this single mobile-first rule is what makes a `w3-row` layout "responsive" without any media queries in the developer's own code, since the breakpoint logic is baked into the framework itself. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`w3-row`** — no-padding row container. **`w3-row-padding`** — same, but with 8px left/right padding per column. [S1]
- **Named fraction classes** — `w3-half` (50%), `w3-third` (33.33%), `w3-twothird` (66.66%), `w3-quarter` (25%), `w3-threequarter` (75%) — ALL collapse to 100% on screens under 601px. [S1]
- **`w3-rest`** — occupies whatever width remains after other fixed/percent-width columns; MUST be the last element in the row's source order. [S1]
- **`w3-col`** — defines one column in a 12-column grid, with a manually specified width (px, %, or plain, unstyled). [S1]
- **Nested rows** — a `w3-row` can be placed entirely inside one column of an outer `w3-row`, for sub-layouts. [S1]
- **`w3-stretch`** — removes left/right margins, useful for stretching a `w3-row-padding` row to the container's full edge-to-edge width. [S1]
- **DP (density-independent pixels)** — W3.CSS's responsiveness thresholds (601px small/medium boundary, 993px medium/large) are based on DP, not raw physical resolution — e.g. an iPhone 6 at 750×1334px resolution is treated as 375×667 DP, i.e. a small screen. [S1]

## 📖 세부 내용 (Details)
- Two-thirds/one-third split: `<div class="w3-row"><div class="w3-green w3-container w3-twothird"><h2>w3-twothird</h2></div><div class="w3-container w3-third"><h2>w3-third</h2></div></div>`. [S1]
- Fixed-width + rest: `<div class="w3-row"><div class="w3-col" style="width:150px"><p>I am 150px</p></div><div class="w3-rest w3-green"><p>I am the rest</p></div></div>` — `w3-rest` must come last. [S1]
- Nested row inside a half-column: a `w3-half` div containing its own inner `w3-row` with two more `w3-half` divs. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **w3-rest의 위치 제약**: w3-rest 클래스를 가진 요소는 반드시 소스코드상 마지막에 위치해야 한다는 점이 명시적으로 요구됨. [S1]
- **DP 기반 반응형 임계값**: 실제 픽셀 해상도가 아니라 DP(밀도 독립 픽셀) 기준으로 화면 크기를 판단한다는 점이 아이폰 6 예시로 증명됨(750×1334 해상도가 375×667 DP의 작은 화면으로 취급). [S1]

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 고정폭 사이드바(150px)+나머지 영역(w3-rest)으로 구성된 레이아웃이 실전 활용의 대표 사례다. [S1]

## 💻 코드 패턴 (Code patterns)
Fixed-width column plus a "rest" column that must come last (HTML):
```html
<div class="w3-row">
  <div class="w3-col" style="width:150px"><p>I am 150px</p></div>
  <div class="w3-rest w3-green"><p>I am the rest</p></div>
</div>
```

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.88
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[W3.CSS Tutorial]]
- **관련 개념:** [[W3CSS Flex Items]], [[W3CSS Cells]], [[W3CSS Responsive]]
- **참조 맥락:** 반응형 행/열 시스템 — 셀(Cells) 레이아웃 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — W3.CSS Rows — https://www.w3schools.com/w3css/w3css_rows.asp

## 📝 변경 이력 (Change history)
- 2026-07-04: Initial draft synthesized from the W3Schools "W3.CSS Rows" page (Astra wiki-curation, P-Reinforce v3.1 format).