JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
  <div class="obal">
    <div class="item">1</div>
    <div class="item">2</div>
    <div class="item">3</div>
    <div class="item">4</div>
    <div class="item">5</div>
    <div class="item">6</div>
    <div class="item">7</div>
  </div>
</div>

CSS

* {
  font-size: 30px;
  font-weight: bold;
  font-family: sans-serif;
}

.container {
  width: 800px; 
  height: 600px;
  margin-left: auto;
  margin-right: auto;
  border: 10px solid black;
}

.obal {
  display: grid;
  border: 10px solid red;
  grid-template-columns: 20% 20% 60%;
  grid-gap: 20px;
}

.item {
  background: #ffaa00;
  display: grid;
  justify-content: center;
  align-content: center;
}