JSFiddle - React, Tailwind, and code Playground

HTML

<div class="content-wrapper">
  <div class="main">
    <div class="sidebar-menu"></div>
    <div class="infinite-scroll-component">
      <div class="main-panel">
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
        <h1>PEPE</h1>
       ...

CSS

body, html {
    height: 100%;
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}

body {
  width: 100%;
  overflow: auto;
}

.main, .main-panel {
    flex: 1;
}

.content-wrapper, .main {
    display: flex;
}

.content-wrapper {
    flex: 1;
    overflow: hidden;
    flex-direction: column;
    height: 100%;
}

.sidebar-menu {
    background: #2f2f2f;
    color: #fff;
    display: flex;
    flex-direction: column;
    width: 200px;
    overflow-y: auto;
}

.infinite-scroll-component {
    flex: 1 1 0px;
    display: flex;
    overflow-y: auto;
    overflow-x: hidden;
    will-change: contents;
    transform: translateZ(0);
    background: yellow;
}

.main-panel {
    margin: 0;
    width: 100%;
    padding: 30px 30px 0;
    display: flex;
    flex-direction: column;
    max-width: 100%;
}