counter-reset : counter 초기화 counter-increment : counter 값 증가시키는 거 counter() or counters() function : counter값 추가 또는 적용 ol { counter-reset: section; } li { counter-reset: subsection; } li::before { counter-increment: section; content: counter(section); } 종류 어떤거 있는지 나중에 추가하기 https://developer.mozilla.org/en-US/docs/Web/CSS/counter-reset