<h2>Introdução</h2>
<h2>Início</h2>
<h2>Meio</h2>
<h2>Fim</h2>
<h2>Referências</h2>
body {
  counter-reset: section;
}

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

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