JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container-big">
  <div class="header-big">HEADER 1</div>
     <div class="content-big">
      <div class="container">
      <div class="header">HEADER 2</div>
         <div class="content">
            <div class="fill f1"></div>
            <div class="fill f2"></div>
            <div class="fill f1"></div>
            <div class="fill f2"></div>
            <div class="fill f1"></div>
            <div class="fill f2"></div>
            <div class="fill f1"></div>
            <div class="fill f2"></div>
            <div class="fill f1"></div>
            <div class="fill f2"></div>
            <div class="fill f1"></div>
            <div class="fill f2"></div>
            <div class="fill f1"></div>
            <div class="fill f2"></div>
            <div class="fill f1"></div>
            <div class="fill f2"></div>
            <div class="fill f1"></div>
            <div class="fill f2"></div>
            <div class="fill f1"></div>
            <div class="fill f2"></div>
            <div class="fill f1"></div>
            <div class="fill f2"></div>
            <div class="fill f1"></div>
            <div class="fill f2"></div>
            <div class="fill f1"></div>
            <div class="fill f2"></div>
            <div class="fill f1"></div>
            <div class="fill f2"></div>
            <div class="fill f1"></div>
            <div class="fill f2"></div>
         </div>
      </div>
   </div>
</div>

CSS

.container-big {  
  background: blue; 
  height: 600px; 
  width: 250px; 
}

.container {  
  background: lightblue; 
  height: 100%; 
  width: 95%; 
  padding:0 2%;
}

.header-big{
    background: yellow; 
    height:30px;
    width:100%;
}

.header{
    background: lightyellow; 
    height:30px;
    width:100%;
}

.content-big { 
  height: : calc(100% - 30px); 
  width: 100%; 
  overflow-y:auto;
}

.content { 
  max-height: calc(100% - 30px); 
  max-width: 100%; 
  overflow-y:auto;
}

.fill{
  height: 40px; 
  width: 100%; 
}

.f1{
    background: grey; 
}
.f2{
  background: brown;
}