---
id: w3css-color-themes
title: "W3CSS Color Themes"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["w3-theme-*", "predefined themes", "theme gradient", "W3.CSS 컬러 테마"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.85
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["w3css", "css-framework", "w3schools", "colors", "theming"]
raw_sources: ["https://www.w3schools.com/w3css/w3css_color_themes.asp"]
applied_in: []
github_commit: ""
---

# [[W3CSS Color Themes]]

## 🎯 한 줄 통찰 (One-line insight)
A W3.CSS "theme" requires ZERO class-name changes in the HTML — retheming an entire app is just swapping which theme STYLESHEET is linked (e.g. `w3-theme-indigo.css` → `w3-theme-blue.css`), because theme CSS files redefine the SAME `w3-theme-*` class names to different color values, meaning the markup stays identical across every theme and only the linked file changes. [S1]

## 🧠 핵심 개념 (Core concepts)
- **Theme-swap mechanism** — link the base `w3.css` plus one theme file (e.g. `w3-theme-indigo.css`); switching themes means changing only the second `<link>`, not any HTML. [S1]
- **~22 predefined downloadable themes** — red, pink, purple, deep-purple, indigo, blue, light-blue, cyan, teal, green, light-green, lime, khaki, yellow, amber, orange, deep-orange, blue-grey, brown, grey, dark-grey, black, plus a special `w3-theme-w3schools`. [S1]
- **`w3-theme-gradient`** — a community-contributed addition (explicitly credited to "one reader['s] suggestion") layering a linear-gradient using the theme's l1/l2 shade variables, requiring the same four vendor-prefix declarations covered in the Validation chapter. [S1]
- **Theme reuse in Mobile app UI** — the same Movies-2014 app mockup from the Mobile chapter reappears here restyled purely via a different theme link, demonstrating the theme-swap claim concretely. [S1]

## 📖 세부 내용 (Details)
- Applying a theme requires only linking two stylesheets: `<link rel="stylesheet" href="https://www.w3schools.com/w3css/5/w3.css"><link rel="stylesheet" href="https://www.w3schools.com/lib/w3-theme-indigo.css">`. [S1]
- Vendor-prefixed gradient built from theme shade variables: `.w3-theme-gradient { color: #000 !important; background:-webkit-linear-gradient(top,#64B5F6 25%,#42A5F5 75%)}` (repeated for `-moz-`, `-o-`, `-ms-`, and unprefixed). [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **HTML 변경 없이 전체 리테마 가능**: 테마를 바꾸려면 링크된 CSS 파일 하나만 교체하면 되고 HTML의 클래스명은 전혀 손댈 필요가 없다는 점이 명시적으로 확인됨(동일 클래스명을 테마 파일마다 다르게 정의하는 방식). [S1]

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — Mobile 챕터의 동일한 앱 목업이 테마 파일만 교체해 다른 색상으로 렌더링되는 것이 테마 시스템의 실전 활용을 직접 보여주는 사례다. [S1]

## 💻 코드 패턴 (Code patterns)
Switching an entire app's color theme by changing only the linked stylesheet (HTML/CSS):
```html
<link rel="stylesheet" href="https://www.w3schools.com/w3css/5/w3.css">
<link rel="stylesheet" href="https://www.w3schools.com/lib/w3-theme-indigo.css">
<!-- Swap the second link to w3-theme-blue.css to retheme without touching any HTML -->
```

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.85
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[W3.CSS Tutorial]]
- **관련 개념:** [[W3CSS Color Schemes]], [[W3CSS Mobile]], [[W3CSS Versions]], [[W3CSS Validation]]
- **참조 맥락:** Color Reference 섹션 마지막 — Web Building 크래시코스 섹션으로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — W3.CSS Color Themes — https://www.w3schools.com/w3css/w3css_color_themes.asp

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