JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrap">
  <!-- <div class="space"></div> -->
  <div class="page">
    Основное содержание.
  </div>
  <!-- <div class="space"></div> -->
</div>

CSS

.wrap {
}

/* .space {
  float: left;
  min-height: 1px;
  width: 5%;
  background: red;
} */

.page {
  box-sizing: border-box;
  width: 100%;
  background: pink;
  border-left: 20px skyblue solid;
  border-right: 20px skyblue solid;
}