2nd/10_Wiki/Topics/Domain_Programming/Topic_CSS/CSS_Counters.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-counters	CSS Counters	Frontend	draft	conceptual		CSS counters counter-reset counter-increment automatic numbering counter() function		B	0.89	2026-06-23	2026-06-23			css web frontend w3schools counters generated-content	https://www.w3schools.com/css/css_counters.asp

CSS Counters

🎯 한 줄 통찰 (One-line insight)

CSS counters are "variables" maintained by CSS whose values can be incremented (or decremented) by CSS rules, enabling automatic numbering of elements like section headings — no JavaScript required. [S1]

🧠 핵심 개념 (Core concepts)

• What counters are — CSS counters are "variables" maintained by CSS, and their values can be incremented (or decremented) by CSS rules. [S1]
• counter-reset — creates or resets a counter. [S1]
• counter-increment — increments (or decrements) a counter value. [S1]
• content — inserts generated content (used with ::before/::after). [S1]
• counter() — adds/returns the value of a named counter to an element. [S1]
• Increment direction & amount — counter-increment takes a second parameter (default 1); a negative value decrements, and any value can be used to step by more than 1. [S1]

🧩 추출된 패턴 (Extracted patterns)

• Reset on container, increment on item — set counter-reset on a container (e.g., body) and counter-increment on the repeated element's ::before. [S1]
• Compose generated labels — combine string literals with counter(name) inside content to produce labels like "Section 1: ". [S1]
• Tune the step — change numbering direction/granularity purely by the second argument of counter-increment (e.g., -1, 2). [S1]

📖 세부 내용 (Details)

CSS Automatic Numbering With Counters CSS counters are "variables" maintained by CSS, and their values can be incremented (or decremented) by CSS rules. The properties/functions used are: counter-reset (creates or resets a counter), counter-increment (increments/decrements a counter value), content (inserts generated content), and counter() (adds the value of a counter to an element). [S1]

CSS Increase and Decrease Counter The following example creates a counter for the page (in the body selector), then increments the counter value by 1 for each <h2> element, adding "Section <value>: " before each <h2>: [S1]

body {
  counter-reset: section;
}

h2::before {
  counter-increment: section;
  content: "Section " counter(section) ": ";
}

Decrementing a Counter The counter-increment property has a second parameter. The default value is 1. To decrease the counter value, you can set it to -1: [S1]

body {
  counter-reset: section;
}

h2::before {
  counter-increment: section -1;
  content: "Section " counter(section) ": ";
}

Incrementing by Custom Values You can increment the counter by any value. Here we increment by 2: [S1]

body {
  counter-reset: section;
}

h2::before {
  counter-increment: section 2;
  content: "Section " counter(section) ": ";
}

🛠️ 적용 사례 (Applied in summary)

The page's examples are the applied cases: numbering <h2> headings as "Section 1:", "Section 2:", etc., plus variants that decrement (-1) and step by 2. No external project/commit applications found in the source.

💻 코드 패턴 (Code patterns)

Basic auto-numbering (language: CSS):

body {
  counter-reset: section;
}

h2::before {
  counter-increment: section;
  content: "Section " counter(section) ": ";
}

Custom step (language: CSS):

h2::before {
  counter-increment: section 2;
}

⚖️ 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 Nested Counters, CSS Pseudo-elements, CSS Lists
• 참조 맥락: Referenced when generating automatic numbering for headings, lists, or sections without scripting.

📚 출처 (Sources)

• [S1] W3Schools — CSS Counters — https://www.w3schools.com/css/css_counters.asp

📝 변경 이력 (Change history)

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