<div class="flex-container">
  <div class="flex-item">1</div>
  <div class="flex-item">2</div>
  <div class="flex-item">3</div>
</div>

.flex-container {
  display: flex;
  flex-direction: row;
  flex-wrap: nowrap;
  justify-content: flex-start;
  align-items: stretch;
  align-content: stretch;
  gap: 10px;
}

.flex-item {
  order: 0;
  flex-grow: 0;
  flex-shrink: 1;
  flex-basis: auto;
  align-self: auto;
}