JSFiddle - React, Tailwind, and code Playground

HTML

<header></header>

CSS

header {
            background: url("http://4.bp.blogspot.com/-7JOgZCEsSLw/USawrns4kUI/AAAAAAAAAP8/sVjCadMg-f4/s1600/Winter-is-coming11.png") no-repeat center; 
            /* Change back address of image */
            background-size: 100% 100%;
            height: 300px; 
            /* Change height back to 630px */
        }
        html, body {
            padding:0px;
            margin:0px;
        }