JSFiddle - React, Tailwind, and code Playground

HTML

<div id="wrapper">
    <div id="one">bgfgf</div>
    <div id="two">
        <iframe id="frame" src="abc.html"></iframe>
    </div>
  </div>
</div>

CSS

#wrapper {height:350px; width:300px; border:3px solid gray; display:table;}
#one {height:100px; background-color:red;}
#two {background-color:blue; height: 300px;}
iframe {width:100%; height:100%; background:white;-webkit-box-sizing:border-box; -moz-box-sizing:border-box; box-sizing:border-box;}
#frame {border: 1px solid black; height: 100%;}