JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <div id="wrapper">
        <div id="menu">
            1
        </div>
        <div id="content">2
            <div id="half_of_content">2.1</div>
        </div>
        <div id="footer" style="">
            3
        </div>
    </div>
</body>

CSS

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

#wrapper {
    display: flex;
  flex-flow: column;
    height: 100%;
}

#menu {
    height: 70px; 
    background-color: purple
}

#content {
    flex: 1;
    height: 100%;
    background-color: green;
    position: relative;
}

#half_of_content {
    height: 50%;
    background-color: yellow;
    position: absolute;
    width: 100%;
}

#footer {
    height: 100px; 
    background-color: cyan
}