2nd/10_Wiki/Topic_CSS/CSS_Clear_Clearfix.md

---
id: css-clear-and-clearfix
title: "CSS Clear and Clearfix"
category: "Frontend"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["clear", "clearfix", "clearfix hack", "CSS clear", "clear both", "float clearing"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.88
created_at: 2026-06-23
updated_at: 2026-06-23
review_reason: ""
merge_history: []
tags: ["css", "web", "frontend", "w3schools", "float", "clear", "layout"]
raw_sources: ["https://www.w3schools.com/css/css_float_clear.asp"]
applied_in: []
github_commit: ""
---

# [[CSS Clear and Clearfix]]

## 🎯 한 줄 통찰 (One-line insight)
The `clear` property stops elements from wrapping around floated content, and the clearfix hack (an `::after` pseudo-element with `clear: both`) forces a container to expand to include its floated children. [S1]

## 🧠 핵심 개념 (Core concepts)
- **clear purpose** — the `clear` property specifies behavior for elements adjacent to floated content; it prevents elements from wrapping around or beside the floated content. [S1]
- **none (default)** — allows floating on either side. [S1]
- **left** — pushes the element below left-side floats. [S1]
- **right** — pushes the element below right-side floats. [S1]
- **both** — pushes the element below floats on both sides. [S1]
- **inherit** — inherits the parent's clear value. [S1]
- **clearfix problem** — when floated elements exceed their container's height, they overflow the container. [S1]
- **clearfix solution** — use the `::after` pseudo-element to contain floats properly. [S1]

## 🧩 추출된 패턴 (Extracted patterns)
- **Drop below a float** — set `clear` (e.g. `clear: left`) on the next element to push it below the float instead of beside it. [S1]
- **Clearfix hack** — add an `::after` pseudo-element with empty content, `clear: both`, and `display: table` to make a parent contain its floated children. [S1]

## 📖 세부 내용 (Details)
**The clear property** [S1]
The `clear` property specifies behavior for elements adjacent to floated content. It prevents elements from wrapping around or beside the floated content.

**Clear property values** [S1]

| Value | Behavior |
|-------|----------|
| none | Allows floating on either side (default) |
| left | Pushes element below left-side floats |
| right | Pushes element below right-side floats |
| both | Pushes element below floats on both sides |
| inherit | Inherits parent's clear value |

**Clear example** [S1]
```css
div1 {
  float: left;
}

div2 {
  clear: left;
}
```

**The clearfix hack** [S1]
When floated elements exceed container height, they overflow. The clearfix solution uses the `::after` pseudo-element to contain floats properly.

```css
.clearfix::after {
  content: "";
  clear: both;
  display: table;
}
```

**How it works** [S1]
- `.clearfix::after` targets the pseudo-element generated after the element's content.
- `content: ""` renders the pseudo-element despite having no visible content.
- `clear: both` pushes following content below floated elements and expands the parent container.
- `display: table` establishes a new block formatting context for containing floats.

The page notes: "This clears both left and right floats, effectively pushing any following content below the floated elements, and forces the parent container to expand to include them." [S1]

## 🛠️ 적용 사례 (Applied in summary)
The page's applied examples are a `clear: left` element dropped below a left-floated sibling, and a `.clearfix` container that uses `::after { content: ""; clear: both; display: table; }` to expand around its floated children. No external project/commit applications found in the source.

## 💻 코드 패턴 (Code patterns)
Push an element below a left float (language: CSS):
```css
div1 {
  float: left;
}

div2 {
  clear: left;
}
```

Clearfix hack to contain floats (language: CSS):
```css
.clearfix::after {
  content: "";
  clear: both;
  display: table;
}
```

## ⚖️ 비교 및 선택 기준 (Comparison & decision criteria)
- **none** — default; element may sit beside floats. [S1]
- **left / right** — drop the element below floats on that one side. [S1]
- **both** — drop below floats on either side; used inside the clearfix hack. [S1]
- **inherit** — take the parent's clear value. [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:** 0.88
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[CSS Tutorial]]
- **관련 개념:** [[CSS Float]], [[CSS Overflow]], [[CSS Position Fixed and Absolute]]
- **참조 맥락:** Referenced whenever floated elements must be cleared or a container must expand to contain its floats.

## 📚 출처 (Sources)
- [S1] W3Schools — CSS Clear and Clearfix — https://www.w3schools.com/css/css_float_clear.asp

## 📝 변경 이력 (Change history)
- 2026-06-23: Initial draft synthesized from the W3Schools "CSS Clear and Clearfix" page (Astra wiki-curation, P-Reinforce v3.1 format).