forcing user to turn device into landscape mode

dabblet.css

/**
 * forcing user to turn device into landscape mode
 * http://forum.selfhtml.org/self/2015/jul/25/website-darstellung-in-den-landscape-modus-zwingen/1646490#m1646490
 */

@media (orientation: portrait) and (max-width: 20em)
{
	html::after
	{
		position: absolute;
		top: 0;
		right: 0;
		bottom: 0;
		left: 0;
		background: black;
		color: white;
		font-size: 100vmin;
		content: "⤺";
		text-align: center;
	}
}

dabblet.html

<p>Pretty landscape, hunh?</p>

dabblet.js

// alert('Hello world!');

settings.json

{"view":"split-vertical","fontsize":"100","seethrough":"","prefixfree":"1","page":"css"}