JSFiddle - React, Tailwind, and code Playground

HTML

<div class="outer">
  <div class="middle">
    <div class="inner">
         hello
    </div>
  </div>
</div>

<div class="outer">
  <div class="middle">
    <div class="inner2">
         hello
    </div>
  </div>
</div>

CSS

.outer {
  display: flex;
  background: yellow;
  padding: 10px;
}

.middle {
  display: flex;
  flex-shrink: 0;
  background: red;
  padding: 10px;
}

.inner {
  flex-basis: 258px;
  flex-shrink: 0;
  display: flex;
  flex-grow: 0;
  background: green;
}

.inner2 {
  width: 258px;
  flex-shrink: 0;
  display: flex;
  flex-grow: 0;
  background: green;
}