JSFiddle - React, Tailwind, and code Playground

HTML

<body>
<div class="header">Header
    <div class="sub-header">Sub-Header</div>
</div>
<div class="main-content">Auto adjust size</div>
<div class="footer">footer</div>
</body>

CSS

body, html {
    padding: 0;
    margin: 0;
}
.header {
    padding-top: 5px;
    background-color: red;
    width: 100%;
}
.sub-header {
    padding: 5px;
    margin: 0px;
    background-color: yellow;
    width: 100%;
}
.main-content {
    padding: 5px;
    background-color: blue;
    width: 100%;
    
    /* Add minimum height below */
    min-height: 300px;
}
.footer {
    /* position: absolute;
    bottom: 0;
    */
    padding: 5px;
    background-color: green;
    width: 100%;
}
@media screen and (max-width: 320px) {
    .sub-header {
        display: none;
    }
}
}