Tailwind CSS class .flex-initial

<div class="flex bg-gray-200">
  <div class="flex-initial bg-teal-400 p-4 m-2">1</div>
  <div class="flex-initial bg-teal-400 p-4 m-2">2</div>
  <div class="flex-initial bg-teal-400 p-4 m-2">3</div>
</div>

.flex-initial {
    flex: 0 1 auto;
}