JSFiddle - React, Tailwind, and code Playground

by danield770

HTML

<iframe width="560" height="315" src="//www.youtube.com/embed/TEH4G2Qsk2U" frameborder="0" allowfullscreen></iframe>

CSS

body {
    margin:0;
}

iframe {
    width: 100vw; 
    height: 56.25vw; /* 100/56.25 = 560/315 = 1.778 */
    background:red;  
}