Plotting like ggplot2 with TikZ/LatexDessiner comme ggplot2 avec TikZ/LateX

I appreciate the graphics drawn by the ggplot2 package with R, results are nice and elegant. I decided to imitate the style of ggplot2 with TikZ. Here is a working example:

% Gauthier Vermandel 2014
 	axis background/.style={fill=mygrey},
	tick style=mygrey2,
	tick label style=mygrey2,
	xtick pos=left,
	ytick pos=left,
	tick style={
		major grid style={style=white,line width=1pt},minor grid style=mygrey3,
		tick align=outside,
	minor tick num=1,
		\addplot {1/sqrt(2*pi)*exp(-x^2/2)};