JSFiddle - React, Tailwind, and code Playground

HTML

<div class="suche">
  <form name="form1" method="post">
    <input type="text" name="firma" id="tags" placeholder="Firmennamen:" required>
    <p id="kunden">
      <input type="checkbox" name="gesperrt" id="gesperrt" value="1" >
      <label for="gesperrt" style="width:31em;">gesperrte Kunden einblenden</label>
    </p>
    <input type="submit" name="abschicken" id="abschicken" value="Filtern" class="ok">
  </form>
</div>

CSS

#tags:valid + p {
    display:none;
}