JSFiddle - React, Tailwind, and code Playground

HTML

<header></header>
<div id="container">
    <section id="menuleft"></section>
    <section id="menuright"></section>
    <div id="content">
        <div id="contop">top</div>
        <div id="conbot">bottom</div>
    </div>
    
</div>

CSS

html, body {
    height: 100%;
    width: 100%;
    margin: 0;
    padding: 0;
}

header {
    width: 100%;
    height: 30px;
    position: fixed;
    background-color: blue;
}

header {
    top: 0;
    z-index: 9999;
}

#container {
    position: absolute;
    top: 30px;
    bottom: 10px;
    width: 100%;
}

#contop {
    background-color: cyan;
    width: 100%;
    height: 70%;
}

#conbot {
    background-color: red;
    width: 100%;
    height: 100px;
    position: relative;
    bottom: 0px;
    
}

#menuleft {
    height: 100%;
    background-color: purple;
    
}

#menuright, #content {
    height: 100%;
    background-color: green;
    
}


#menuleft {
    width: 100px;
    margin-left: 0px;
    float: left;
}

#menuright {
    width: 100px;
    margin-right: 0px;
    float: right;
}




#content {
    margin: 0px 120px 0px 120px;
    width: auto;
}