usetikzlibrary{positioning}
%...
usetikzlibrary{decorations.pathmorphing}

tikzset{
    input/.style={
        circle,
        draw,
        Blue,
        minimum width = 2
    },
    %...
    labe/.style={
        fill=white,
        fill opacity=0.6,
        text opacity=1,
        font={footnotesizeitshape}
    }
}