JSFiddle - React, Tailwind, and code Playground

HTML

<div class="main">
  <div class="top">top</div>
  <div class="left">left</div>
  <div class="content">
    content
  
  </div>
</div>

CSS

html,body{
  margin:0;
  color:#ddd;
}
.main{
  position:relative;
  width:90%;
  height:100vh;
  margin:0 auto;
  border-top:1px solid transparent;
}
.top{
  position:fixed;
  width:90%;
  height:100px;
  background:#000;
  z-index:2;
}
.left{
  position:fixed;
  width:100px;
  top:102px;
  bottom:0px;
  background:#900;
  z-index:1;
}
.content{
  background:#090;
  margin:101px 0 0 101px;
    height:200vh;
}