JSFiddle - React, Tailwind, and code Playground

HTML

<div id="wrapper">
    <div id="header">
        <div id="grid-left">
            <p>Grid left</p>
        </div>
        <div id="grid-right">
            <p>Grid right</p>
        </div>
    </div>
</div>

CSS

#wrapper {
    height:100%;
    width:98.5%;
    min-width:1024px;
    max-width:1300px;
    margin:0 auto;
    border:1px dashed #222;
}

#header {
    overflow:hidden;
}

#grid-left {
    width:45%;
    float:left
}

#grid-right {
    width:54%;
    float:right
}