Je teste

<!DOCTYPE html>
<html lang="fr">
<head>
  <meta charset="UTF-8">
  <title>Les grilles CSS</title>
<style>
  body {
    text-align: center;
  }
  #conteneur {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    grid-template-rows:
	repeat(4, minmax(75px, auto));
    grid-gap: 10px;
    max-width: 480px;
    margin: 0 auto;
  }
  .un {
    background-color: red;
    grid-column: 1/3;
  }
  .deux {
    background-color: green;
    grid-column: 3/7;
  }
  .trois {
    background-color: blue;
    grid-column: 1/4;
    grid-row: 2/4;
  }
  .quatre {
    background-color: yellow;
    grid-column: 4/7;
    grid-row: 2/4;
  }
  .cinq {
    background-color: black;
    grid-column: 3/7;
  }
  .six {
    background-color: gray;
    grid-column: 1/3;
    grid-row: 4;
  }
</style>
</head>
<body>
  <div id="conteneur">
    <div class="un"></div>
    <div class="deux"></div>
    <div class="trois"></div>
    <div class="quatre"></div>
    <div class="cinq"></div>
    <div class="six"></div>
  </div>
</body>
</html>