css

width: fit-content;
block-size: fit-content;

html

<div class="container">
  <div class="item">Item</div>
  <div class="item">Item with more text in it.</div>
  <div class="item">
    Item with more text in it, hopefully we have added enough text so the text
    will start to wrap.
  </div>
</div>

css

.container {
  border: 2px solid #ccc;
  padding: 10px;
  width: 20em;
}

.item {
  width: fit-content;
  background-color: #8ca0ff;
  padding: 5px;
  margin-bottom: 1em;
}