Sstrhsrtj

I have the following code: But the node is always hidden by the vertical line, how can I solve this? (world and first are hidden by the vertical line. )

begin{tikzpicture}

    polygon{6}{1}{1,4}{cyan}

    polygon[xshift=3cm]{7}{1}{1,2,4,7}{cyan}

    polygon[xshift=8cm]{8}{3}{5,6,1,4}{cyan}

end{tikzpicture}







pgfdeclarelayer{-1}

pgfsetlayers{-1,main}

tikzset{zlevel/.style={%

    execute at begin scope={pgfonlayer{#1}},

    execute at end scope={endpgfonlayer}

}}



tikzset{every picture/.style=thick}

begin{figure}[h]

begin{tikzpicture}[

scale=0.6, every node/.style={scale=0.6}

,every node/.append style={very thick,rounded corners=0.1mm}

]

%begin{pgfonlayer}{tp}    % select the background layer



node[draw,rectangle] (Server) at (9,0) {Remote};



begin{scope}[zlevel=main]

node[draw=blue!50,rectangle,thick] (Network) at (0,-1) {first};

end{scope}







%obj1

begin{scope}[zlevel=main]

node[draw=blue!50,rectangle,thick] (Network) at (0,-2.5) {world};

end{scope}

%end{pgfonlayer}



node[draw=blue!60, rectangle,thick] (Network) at (0,-4.5) {hallo};



begin{scope}[zlevel=-1]

draw  (User)  --  (Network)--(0,-10);

end{scope}

begin{scope}[zlevel=-1]

draw [very thick] (Server)--++(0,-10);

end{scope}

end{tikzpicture}

end{figure