JSFiddle - React, Tailwind, and code Playground

HTML

<h1>Пример резиновой верстки </h1>
<div class="flex">
  <div class="box"></div>
  <div class="box"></div>
  <div class="box"></div>
</div>

CSS

h1 {
  font-size: 5vw;
}
.flex {
  gap: 10px;
  display: flex;
  flex-flow:wrap;
}
.box {
  border: 1px solid black;
  height: 200px;
  min-width: 30%;
}
@media (max-width: 500px){
  .box {
    width: 100%;
  }
}