\usetikzlibrary{positioning,arrows,matrix,shadings} 

\tikzset{
    	% Standardpfeilspitze
   	 >=,
	% Knotenabstand
	on grid=false,
	node distance=0.5cm,
	% Stile
	osGen/.style={
		rectangle,
		rounded corners,
		minimum height=0.8cm,
		minimum width=2.5cm,
		text centered
	},
	osPC/.style={
		draw=red, very thick,
		fill=red!50,},
	osTab/.style={
		draw=yellow, very thick,
		fill=yellow!50,},
	osPhone/.style={
		draw=blue, very thick,
		fill=blue!50,
	},
	osMob/.style={
		draw=green, very thick,
		fill=green!50,
	},
	osEmb/.style={
		draw=gray, very thick,
		fill=gray!50,
	},
	osMobEmb/.style={
        shade,
		draw=green,very thick,
		top color=green!50,
		bottom color=gray!50,
	},
	osMobPC/.style={
        shade,
		draw=green,very thick,
		top color=green!50,
		bottom color=red!50,
	},
	osMobPCEmb/.style={
        shade,
		draw=red,very thick,
		top color=green!50,
		bottom color=gray!50,
	},
	osPhonePCEmb/.style={
        shade,
		draw=red,very thick,
		top color=blue!50,
		bottom color=gray!50,
	},
	osTabPC/.style={
        shade,
		draw=red,very thick,
		top color=yellow!50,
		bottom color=red!50,
	},
	osPCEmb/.style={
        shade,
		draw=red,very thick,
		top color=red!50,
		bottom color=gray!50,
	},
	osLegend/.style={
		minimum height=0.4cm,
		minimum width=0.4cm,
	},
	osLegendText/.style={
		minimum width=2.3cm,
		text width=2.3cm,
	},
	% Pfeilstile
	pui/.style={
		->,
		thick,
		black,
		>=latex
	},
	pkrn/.style={
		->,
		thick,
		orange,
		>=latex
	}
}