The first commented line is your dabblet’s title

dabblet.css

/**
 * The first commented line is your dabblet’s title
 */

html {
	background: #f06;
	background: linear-gradient(45deg, #f06, yellow);
	min-height:100%;
}

div { width: 220px; height: 100px; background: white; }

div:hover { background: black; }

dabblet.html

<div>foo bar</div> 

settings.json

{"page":"css","view":"split"}