2nd/10_Wiki/Topic_CSS/CSS_Counters_Nested.md

---
id: css-nested-counters
title: "CSS Nested Counters"
category: "Frontend"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["CSS nested counters", "counters() function", "multi-level numbering", "section subsection numbering", "nested list numbering"]
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", "counters", "generated-content", "lists"]
raw_sources: ["https://www.w3schools.com/css/css_counters_nested.asp"]
applied_in: []
github_commit: ""
---

# [[CSS Nested Counters]]

## 🎯 한 줄 통찰 (One-line insight)
By running two counters at once — or by using the `counters()` function — CSS can produce multi-level numbering such as "Section 1.1" or outline-style "1.1.1" labels for nested lists, all without JavaScript. [S1]

## 🧠 핵심 개념 (Core concepts)
- **Two counters** — you can maintain more than one counter to number different levels (e.g., a `section` counter for the page and a `subsection` counter reset on each `<h1>`). [S1]
- **`counters()` function** — returns the current values of the named and nested counters, as a string. [S1]
- **`counters()` vs `counter()`** — `counter()` returns the current value of a single named counter; `counters()` returns the named and nested counter values combined into a string. [S1]
- **Separator argument** — `counters(name, separator)` inserts a string (e.g., `"."`) between nesting levels. [S1]

## 🧩 추출된 패턴 (Extracted patterns)
- **Per-level reset** — reset the lower-level counter on the higher-level element (reset `subsection` on each `<h1>`) so it restarts under every parent. [S1]
- **Self-nesting lists** — reset the same counter on every `<ol>` and emit `counters(section,".")` on each `<li>::before` to auto-build hierarchical numbers like 1, 1.1, 1.2. [S1]

## 📖 세부 내용 (Details)
**CSS Using Two Counters**
You can create multiple counters for different numbering levels: a `section` counter for the page and a `subsection` counter for each `<h1>` element. The `section` counter increments on each `<h1>`, while a `subsection` counter (reset on each `<h1>`) increments on each `<h2>`, producing labels like "Section 1." and "1.1". [S1]
```css
body {
  counter-reset: section;
}

h1 {
  counter-reset: subsection;
}

h1::before {
  counter-increment: section;
  content: "Section " counter(section) ". ";
}

h2::before {
  counter-increment: subsection;
  content: counter(section) "." counter(subsection) " ";
}
```

**The CSS counters() Function**
The `counters()` function returns the current values of the named and nested counters, as a string. In this example, the same `section` counter is reset on every `<ol>` and incremented on each `<li>`, and `counters(section,".")` joins the nested values with a `"."` separator to produce outline numbering within an ordered-list structure: [S1]
```css
ol {
  counter-reset: section;
  list-style-type: none;
}

li::before {
  counter-increment: section;
  content: counters(section,".") " ";
}
```

**CSS Counter Properties**
The page lists the following counter-related properties and functions: [S1]

| Property / Function | Description |
| --- | --- |
| `content` | Used with the `::before` and `::after` pseudo-elements, to insert generated content [S1] |
| `counter-increment` | Increments one or more counter values [S1] |
| `counter-reset` | Creates or resets one or more counters [S1] |
| `counter()` | Returns the current value of the named counter [S1] |
| `counters()` | Returns the current values of the named and nested counters [S1] |

## 🛠️ 적용 사례 (Applied in summary)
The page's examples are the applied cases: "Section N." / "N.M" headings produced by two counters, and outline-style "1.1.1" numbering for a nested ordered list via `counters()`. No external project/commit applications found in the source.

## 💻 코드 패턴 (Code patterns)
Two-level heading numbering (language: CSS):
```css
h1::before {
  counter-increment: section;
  content: "Section " counter(section) ". ";
}

h2::before {
  counter-increment: subsection;
  content: counter(section) "." counter(subsection) " ";
}
```
Self-nesting list numbering (language: CSS):
```css
li::before {
  counter-increment: section;
  content: counters(section,".") " ";
}
```

## ⚖️ 비교 및 선택 기준 (Comparison & decision criteria)
- **`counter()`** — use when you need the value of a single counter at one level (e.g., "Section 3"). [S1]
- **`counters()`** — use when you need the named and nested counter values joined into one string for multi-level/outline numbering (e.g., "3.2.1"), supplying a separator argument such as `"."`. [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 Counters]], [[CSS Lists]], [[CSS Pseudo-elements]]
- **참조 맥락:** Referenced when building multi-level outline numbering for headings or nested lists.

## 📚 출처 (Sources)
- [S1] W3Schools — CSS Nested Counters — https://www.w3schools.com/css/css_counters_nested.asp

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