---
id: css-border-sides
title: "CSS Border Sides"
category: "Frontend"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["border sides", "CSS individual borders", "border-top-style", "border per side", "border value count"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.89
created_at: 2026-06-23
updated_at: 2026-06-23
review_reason: ""
merge_history: []
tags: ["css", "web", "frontend", "w3schools", "border", "border-sides"]
raw_sources: ["https://www.w3schools.com/css/css_border_sides.asp"]
applied_in: []
github_commit: ""
---

# [[CSS Border Sides]]

## 🎯 한 줄 통찰 (One-line insight)
In CSS it is possible to specify a different border for each side of an element, either through individual side properties (e.g. `border-top-style`) or through the shorthand `border-style` whose number of values (1–4) determines how the sides are filled. [S1]

## 🧠 핵심 개념 (Core concepts)
- **Different border per side** — in CSS it is possible to specify a different border for each side. [S1]
- **Individual side properties** — `border-top-style`, `border-right-style`, `border-bottom-style`, and `border-left-style` each target one side. [S1]
- **Shorthand value count** — the `border-style` property can take one to four values, and the count controls which sides get which style. [S1]
- **Same logic for width and color** — the same value-count logic applies equally to `border-width` and `border-color`. [S1]

## 🧩 추출된 패턴 (Extracted patterns)
- **Clockwise-from-top rule** — four values map to top, right, bottom, left in clockwise order. [S1]
- **Mirror fill** — with two values, top/bottom share the first and right/left share the second; with three, the second value covers both right and left. [S1]

## 📖 세부 내용 (Details)
**Borders - Individual Sides** [S1]
In CSS, it is also possible to specify a different border for each side.

**Example** — using the four individual side-style properties: [S1]
```css
p {
  border-top-style: dotted;
  border-right-style: solid;
  border-bottom-style: dotted;
  border-left-style: solid;
}
```

The example above gives the same result as the shorthand below. [S1]

**Shorthand: how the value count maps to sides** [S1]

If the `border-style` property has **four values**: [S1]
```css
border-style: dotted solid double dashed;
```
- top border is `dotted`
- right border is `solid`
- bottom border is `double`
- left border is `dashed`

If the `border-style` property has **three values**: [S1]
```css
border-style: dotted solid double;
```
- top border is `dotted`
- right and left borders are `solid`
- bottom border is `double`

If the `border-style` property has **two values**: [S1]
```css
border-style: dotted solid;
```
- top and bottom borders are `dotted`
- right and left borders are `solid`

If the `border-style` property has **one value**: [S1]
```css
border-style: dotted;
```
- all four borders are `dotted`

The `border-style` property is used in the examples above. However, it also works with `border-width` and `border-color`. [S1]

## 🛠️ 적용 사례 (Applied in summary)
The page's own applied examples are the individual side-property stylesheet and the four shorthand declarations (one/two/three/four values) demonstrating each value-count mapping. No external project/commit applications found in the source.

## 💻 코드 패턴 (Code patterns)
Individual side properties (language: CSS):
```css
p {
  border-top-style: dotted;
  border-right-style: solid;
  border-bottom-style: dotted;
  border-left-style: solid;
}
```
Shorthand, four values (top, right, bottom, left):
```css
border-style: dotted solid double dashed;
```

## ⚖️ 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:** 0.89
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[CSS Tutorial]]
- **관련 개념:** [[CSS Border Style]], [[CSS Border Width]], [[CSS Border Color]], [[CSS Border Shorthand]]
- **참조 맥락:** Explains the value-count box-model rule reused across all border (and margin/padding) shorthands.

## 📚 출처 (Sources)
- [S1] W3Schools — CSS Border Sides — https://www.w3schools.com/css/css_border_sides.asp

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