2nd/10_Wiki/Topic_CSS/CSS_Background_Origin.md

---
id: css-background-origin
title: "CSS Background Origin"
category: "Frontend"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["background-origin", "padding-box", "border-box origin", "content-box origin", "background positioning area", "background image start"]
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", "background", "background-origin"]
raw_sources: ["https://www.w3schools.com/css/css3_background_origin.asp"]
applied_in: []
github_commit: ""
---

# [[CSS Background Origin]]

## 🎯 한 줄 통찰 (One-line insight)
The `background-origin` property specifies where the background image is positioned relative to the box model — starting from the padding edge (default), the border edge, or the content edge. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`background-origin`** — specifies where the background image is positioned. [S1]
- **`padding-box`** — the background image starts from the top-left corner of the padding edge; this is the default. [S1]
- **`border-box`** — the background image starts from the top-left corner of the border edge. [S1]
- **`content-box`** — the background image starts from the top-left corner of the content edge. [S1]
- **Fixed-attachment caveat** — this property has no effect if `background-attachment` is set to `fixed`. [S1]

## 🧩 추출된 패턴 (Extracted patterns)
- **Box-model anchor pattern** — the chosen value (`padding-box` / `border-box` / `content-box`) selects which box-model edge the image's top-left corner aligns to. [S1]
- **Default-vs-inset pattern** — `border-box` lets the image extend out under the border, while `content-box` insets it past the padding. [S1]

## 📖 세부 내용 (Details)
**CSS `background-origin` Property**
The `background-origin` property specifies where the background image is positioned. [S1]

The property takes three different values: [S1]
- `padding-box` — the background image starts from the top-left corner of the padding edge. This is default. [S1]
- `border-box` — the background image starts from the top-left corner of the border edge. [S1]
- `content-box` — the background image starts from the top-left corner of the content edge. [S1]

**Note:** This property has no effect if the `background-attachment` property is set to `fixed`. [S1]

Example — the three origin values across three divs: [S1]
```css
#div1 {
  border: 2px solid black;
  padding: 35px;
  background-image: url(img_flwr.gif);
  background-repeat: no-repeat;
  background-origin: padding-box;
}

#div2 {
  border: 2px solid black;
  padding: 35px;
  background-image: url(img_flwr.gif);
  background-repeat: no-repeat;
  background-origin: border-box;
}

#div3 {
  border: 2px solid black;
  padding: 35px;
  background-image: url(img_flwr.gif);
  background-repeat: no-repeat;
  background-origin: content-box;
}
```

**CSS Background Properties**

| Property | Description |
|----------|-------------|
| `background` | A shorthand property for setting all the background properties in one declaration |
| `background-clip` | Specifies the painting area of the background |
| `background-image` | Specifies one or more background images for an element |
| `background-origin` | Specifies where the background image(s) is/are positioned |
| `background-size` | Specifies the size of the background image(s) |

[S1]

## ⚖️ 비교 및 선택 기준 (Comparison & decision criteria)
Choosing the origin value relative to the box model: [S1]
- **`padding-box`** (default) — image's top-left aligns to the padding edge; the usual behavior.
- **`border-box`** — image starts at the border edge, so it appears under the border.
- **`content-box`** — image starts at the content edge, inset past both border and padding.
Note these only affect positioning of the image's origin; with `background-attachment: fixed`, the property has no effect. [S1]

## 🛠️ 적용 사례 (Applied in summary)
The page's three-div example (identical flower image with `padding-box`, `border-box`, and `content-box`) is the applied case. No external project/commit applications found in the source.

## 💻 코드 패턴 (Code patterns)
Anchor the background image to the content edge (language: CSS):
```css
selector {
  border: 2px solid black;
  padding: 35px;
  background-image: url(img_flwr.gif);
  background-repeat: no-repeat;
  background-origin: content-box;
}
```

## ⚖️ 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 Background Clip]], [[CSS Background Size]], [[CSS Multiple Backgrounds]]
- **참조 맥락:** Referenced when controlling exactly where a background image begins relative to border and padding.

## 📚 출처 (Sources)
- [S1] W3Schools — CSS Background Origin — https://www.w3schools.com/css/css3_background_origin.asp

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