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<!DOCTYPE html> <html> <head> <style> body { counter-reset: section; } h2::before { counter-increment: section; content: "Section " counter(section) ": "; } </style> </head> <body> <h1>使用 CSS 计数器：</h1> <h2>HTML 教程</h2> <h2>CSS 教程</h2> <h2>JavaScript 教程</h2> </body> </html>