<div class="grid">
  <div>Direct Child</div>
  <div>Direct Child</div>
  <ul>
    <li>List Item</li>
    <li>List Item</li>
    <li>List Item</li>
  </ul>
  <div>Direct Child</div>
</div>

* {box-sizing: border-box;}

body {
  padding: 2em;
  background-color: rgb(192,181,129);
  color: #333;
  font: 1rem 'Life Savers', cursive;
}

.grid {
  border: 5px solid #fff;
  max-width: 800px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  margin: 2em auto;
  padding: 0;
  gap: 5px;
}

.grid > * {
  background-color: rgba(255,255,255,.5);
  padding: 1em;
  font-weight: bold;
}

ul > * {
  background-color: rgb(209,54,114);
  padding: 1em;
}

ul {
  margin: 0;
  padding: 0;
  list-style: none;
  display: contents;
}