2nd/10_Wiki/Topics/Domain_Programming/Topic_CSS/CSS_HSL.md

id, title, category, status, verification_status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, created_at, updated_at, review_reason, merge_history, tags, raw_sources, applied_in, github_commit

id	title	category	status	verification_status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	created_at	updated_at	review_reason	merge_history	tags	raw_sources	applied_in	github_commit
css-hsl-colors	CSS HSL Colors	Frontend	draft	conceptual		HSL hsl() HSLA hsla() hue saturation lightness CSS HSL values		B	0.88	2026-06-23	2026-06-23			css web frontend w3schools color hsl hsla	https://www.w3schools.com/css/css_colors_hsl.asp

CSS HSL Colors

🎯 한 줄 통찰 (One-line insight)

HSL specifies a color by hue, saturation, and lightness — hsl(hue, saturation, lightness) — and hsla() adds an alpha channel (0.0–1.0) for opacity. [S1]

🧠 핵심 개념 (Core concepts)

• HSL = Hue, Saturation, Lightness. [S1]
• Syntax — hsl(hue, saturation, lightness). [S1]
• Hue — a degree on the color wheel from 0 to 360: 0 (or 360) is red, 120 is green, 240 is blue. [S1]
• Saturation — a percentage value: 0% means a shade of gray, and 100% is the full color. [S1]
• Lightness — a percentage: 0% is black, 50% is neither dark nor light, 100% is white. [S1]
• HSLA — extends HSL with an alpha channel for opacity: hsla(hue, saturation, lightness, alpha), alpha 0.0 (transparent) to 1.0 (opaque). [S1]

🧩 추출된 패턴 (Extracted patterns)

• Saturation controls vividness — lowering saturation toward 0% washes a color out toward gray while keeping hue and lightness fixed. [S1]
• Lightness controls brightness — sweeping lightness from 0% to 100% moves any hue from black through full color to white. [S1]
• Gray via HSL — set hue and saturation to 0 and vary only lightness to produce shades of gray. [S1]

📖 세부 내용 (Details)

HSL Value HSL stands for hue, saturation, and lightness. An HSL color value is specified with hsl(hue, saturation, lightness). Hue is a degree on the color wheel from 0 to 360, where 0 is red, 120 is green, and 240 is blue. Saturation is a percentage value: 0% means a shade of gray, and 100% is the full color. Lightness is also a percentage: 0% is black, 50% is neither dark nor light, and 100% is white. [S1]

Saturation With hue at 0 (red) and lightness at 50%, varying the saturation demonstrates the effect: [S1]

hsl(0, 100%, 50%)
hsl(0, 80%, 50%)
hsl(0, 60%, 50%)
hsl(0, 40%, 50%)
hsl(0, 20%, 50%)
hsl(0, 0%, 50%)

Lightness With hue at 0 (red) and saturation at 100%, varying the lightness demonstrates the effect from no light (black) through full color to full lightness (white). The page shows this across lightness values ranging from 0% to 100%: [S1]

hsl(0, 100%, 0%)    /* 0% = black */
hsl(0, 100%, 100%)  /* 100% = white */

(Intermediate lightness swatches appear on the page but their exact numeric values are: Not found in source.)

Shades of Gray Shades of gray are often defined by setting the hue and saturation to 0 and adjusting the lightness from 0% (black) to 100% (white): [S1]

hsl(0, 0%, 0%)    /* black */
hsl(0, 0%, 100%)  /* white */

(Intermediate gray lightness values between these endpoints are shown as swatches on the page but their exact numeric values are: Not found in source.)

HSLA Value HSLA color values are an extension of HSL with an alpha channel, which specifies the opacity for a color. An HSLA color value is specified with hsla(hue, saturation, lightness, alpha), where the alpha parameter is a number between 0.0 (fully transparent) and 1.0 (not transparent at all). [S1]

The page demonstrates the same color at increasing opacity: [S1]

hsla(9, 100%, 64%, 0)
hsla(9, 100%, 64%, 0.2)
hsla(9, 100%, 64%, 0.4)
hsla(9, 100%, 64%, 0.6)
hsla(9, 100%, 64%, 0.8)
hsla(9, 100%, 64%, 1)

🛠️ 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)

HSL function (language: CSS):

selector {
  color: hsl(hue, saturation, lightness); /* hue 0–360; sat/light 0%–100% */
}

HSLA function with opacity:

selector {
  color: hsla(hue, saturation, lightness, alpha); /* alpha 0.0–1.0 */
}

⚖️ 비교 및 선택 기준 (Comparison & decision criteria)

• HSL vs HSLA — use hsl() for an opaque color described intuitively by hue/saturation/lightness; use hsla() when an opacity (alpha) value from 0.0 to 1.0 is also required. [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 HEX, CSS Colors, CSS Background Color
• 참조 맥락: Referenced whenever a color is described perceptually by hue, saturation, and lightness, or when an opacity channel is needed via HSLA.

📚 출처 (Sources)

• [S1] W3Schools — CSS HSL Colors — https://www.w3schools.com/css/css_colors_hsl.asp

📝 변경 이력 (Change history)

• 2026-06-23: Initial draft synthesized from the W3Schools "CSS HSL Colors" page (Astra wiki-curation, P-Reinforce v3.1 format).