* {
	font-size: 18px;
	font-family: GillSans;
}

#sample-button { 
	height: 55px;
	width: 200px;
	opacity: 0.5;
	top: 50px;
	left: 75px;
	color: #FFFFFF;
	border-radius: 4px;
	border-width: 2px;
	border-color: #000000;
	background-color: #FF0000;
}

.sample-background {
	background-image: url('background.jpg');
	border-color: #DDDDDD;
	border-width: 5px;
}

using Crayon;
using Crayon.MT;

...

var styleContext = new StyleContext (new IOSDeviceContext ());
styleContext.LoadStyleSheet ("style.css");

var button = UIButton.FromType (UIButtonType.Custom);
button.SetStyleId ("sample-button");

var background = new UIView();
background.SetStyleClass ("sample-background");

background.AddSubview(button);