JSFiddle - React, Tailwind, and code Playground

by Gwyn Milcote

HTML

<div class="container">

    <div class="flex side">
        <div class="fixed">
            This content should not scroll
        </div>
    </div>
    
    <div class="flex content">
        <div>
            <p>Scrolling Content</p>
            <p>Scrolling Content</p>
            <p>Scrolling Content</p>
            <p>Scrolling Content</p>
            <p>Scrolling Content</p>
            <p>Scrolling Content</p>
        </div>
    </div>
    
</div>

CSS

html, body {
    padding: 0;
    margin: 0;
}
div {
    box-sizing: border-box;
}

.container {
    display: flex;
    flex-direction: row;
    min-height: 100%;
    align-items: stretch;
}

.flex {
    display: flex;
}
.side {
    background: yellow;
    z-index:5;
    width: 200px;
    padding:5px;
}
.content {
  width: calc(100% - 200px);
    background: green;
    padding: 1rem;
    height: 2000px;
}

.fixed {
    position: fixed;
    width: 200px;
}

@media (max-width: 600px) {
  .container {flex-direction:column;}
  .side {min-height:40px;max-height:60px;}
  .fixed, .side {width:100%}
}