---
id: css-hex-colors
title: "CSS HEX Colors"
category: "Frontend"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["HEX", "hexadecimal color", "#rrggbb", "3-digit HEX", "CSS hex code", "color hex"]
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", "color", "hex"]
raw_sources: ["https://www.w3schools.com/css/css_colors_hex.asp"]
applied_in: []
github_commit: ""
---

# [[CSS HEX Colors]]

## 🎯 한 줄 통찰 (One-line insight)
A HEX color is specified with `#RRGGBB`, where each two-digit hexadecimal pair (00–ff, equal to decimal 0–255) sets the red, green, and blue intensity. [S1]

## 🧠 핵심 개념 (Core concepts)
- **HEX format** — a hexadecimal color is specified with `#RRGGBB`, where the RR (red), GG (green), and BB (blue) hexadecimal integers specify the components of the color. [S1]
- **Range** — each component value is between 00 and ff (the same as decimal 0 to 255). [S1]
- **Red example** — `#ff0000` is displayed as red, because red is set to its highest value (ff) and the others are set to the lowest value (00). [S1]
- **Black and white** — black is `#000000`; white is `#ffffff`. [S1]
- **3-digit shorthand** — the `#rgb` short form works only when both hexadecimal digits within each component pair are the same. [S1]

## 🧩 추출된 패턴 (Extracted patterns)
- **Equal pairs = gray** — when all three pairs hold the same value, the result is a shade of gray. [S1]
- **Shorthand condition** — `#rgb` is a valid abbreviation of `#rrggbb` only when each pair is a doubled digit (e.g. `ff`, `cc`, `99`). [S1]

## 📖 세부 내용 (Details)
**HEX Value**
A hexadecimal color is specified with `#RRGGBB`, where the RR (red), GG (green), and BB (blue) hexadecimal integers specify the components of the color. All values are between 00 and ff. `#ff0000` is displayed as red, because red is set to its highest value (ff) and the others are set to the lowest value (00). Black is `#000000` and white is `#ffffff`. [S1]

Examples of HEX color values shown on the page: [S1]
```css
#ff0000  /* red */
#0000ff  /* blue */
#3cb371  /* medium sea green */
#ee82ee  /* violet */
#ffa500  /* orange */
#6a5acd  /* slate blue */
```

**Shades of Gray**
Shades of gray are often defined using equal values for all three light sources: [S1]
```css
#3c3c3c
#616161
#787878
#b4b4b4
#f0f0f0
#f9f9f9
```

**3 Digit HEX Value**
The 3-digit hex code is a shorthand for some 6-digit hex codes. It is written as `#rgb`, where r, g, and b are repeated to create the full 6-digit form (`#rrggbb`). The 3-digit hex code can only be used when both the values (RR, GG, and BB) are the same for each component. [S1]

Examples of valid 3-digit shorthands: [S1]
```css
#fc9  /* same as #ffcc99 */
#f0f  /* same as #ff00ff */
#b58  /* same as #bb5588 */
```

## 🛠️ 적용 사례 (Applied in summary)
The color values above are the page's own demonstration examples. No external project/commit applications found in the source.

## 💻 코드 패턴 (Code patterns)
6-digit HEX (language: CSS):
```css
selector {
  color: #rrggbb; /* each pair 00–ff */
}
```
3-digit HEX shorthand (only when each pair is a doubled digit):
```css
selector {
  color: #rgb; /* e.g. #f0c == #ff00cc */
}
```

## ⚖️ 비교 및 선택 기준 (Comparison & decision criteria)
- **6-digit vs 3-digit HEX** — use the full `#rrggbb` form for any color; the `#rgb` shorthand is only usable when each component pair is a doubled digit, in which case it produces an identical color with fewer characters. [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 RGB]], [[CSS HSL]], [[CSS Colors]], [[CSS Background Color]]
- **참조 맥락:** Referenced whenever a color is specified as a hexadecimal code, the most common form in stylesheets.

## 📚 출처 (Sources)
- [S1] W3Schools — CSS HEX Colors — https://www.w3schools.com/css/css_colors_hex.asp

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