<style type="text/css">
    @media (prefers-color-scheme: dark) {
      table {
        background-color: white !important;
        color: black !important;
      }
    }
  </style>
  <table style="background: #ffffff !important; color: black!important;">
    Тело письма
  </table>

const replacer = regex => string.replace(regex, (match, urlString) => {
      if (match.includes(baseUrlPath)) {
        return match;
      };
      //////// some code
    });

if (match.includes(baseUrlPath)) {
        return match;
      };