Dark Mode support for the "Learn Vimscrip The Hard Way"

learnvimthehardway_darkmode_support.css

@media (prefers-color-scheme: dark) {
	body {
		background: #202020;
		color: silver;
	}
	
	a {
		color: white;
	}
	
	h1,h2,h3 {
		font-weight: 900;
		color: gold;
	}
	
	.codehilite, code {
		background: black;
		color: green;
	}
}