JSFiddle - React, Tailwind, and code Playground

HTML

<div class='main'>
  <div class='menu'>111
  </div>
  <div class='content'>222
  </div>
</div>

CSS

.main {
    padding-left: 210px;
    overflow: hidden;
}

.menu {
    float: right;
    width: 200px;
}

.content {
    margin-left: -210px;
    float: left;
    width: 100%;
}