JSFiddle - React, Tailwind, and code Playground

HTML

<?php wp_footer(); ?><div id="footer" style="width: 690px;">

CSS

#encase {
width: 100%;
height: 100%; 
margin-left: auto;
margin-right: auto;
}
#header {
background-color:black;
width: 1490px;
height:110px;
margin-left: auto;
margin-right: auto;
padding: 5px;
}
#topNav {
background-color:green;
width: 1490px;
height: 50px;
margin-left: auto;
margin-right: auto;
padding: 5px;
}
#wholeBody {
background-color: red;
width: 1490px;
height: 690px;
margin-left: auto;
margin-right: auto;
padding: 5px;
}
#sideNav {
    float:left;
background-color: yellow;
width: 290px;
height: 690px;
/*margin-left: 10.25%;*/
padding: 5px;
}
#body1 {
background-color: purple;
width: 1190px;
height: 690px;
margin-left: 16%;
padding: 5px;

}
#footer {
background-color: blue;
width: 1490px;
height: 110px;
margin-left: auto;
margin-right: auto;
padding: 5px;
}