<ul class="item">
  <li class="item__list">
    横並びにする
  </li>
  <li class="item__list">
    横並びにする
  </li>
  <li class="item__list">
    横並びにする
  </li>
</ul>
ul,li {
  margin: 0;
  padding: 0;
}

li {
  list-style-type: none;
}

.item {
  display: grid;
  gap: 10px;
  grid-auto-flow: column;
}

.item__list {
  border: 1px solid #ccc;
}

External CSS

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External JavaScript

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