# Tikz, issue with applying style to nodes

I am a beginner in LaTeX, especially in TikZ package.

I want to draw Peterson graph with some styles.

My code

\documentclass{article}

\usepackage{tikz}
\usepackage{caption}
\usepackage{graphicx}

\usetikzlibrary{graphs}
\usetikzlibrary{graphs.standard}
\usetikzlibrary[graphs]

\tikzset{
every node/.style={draw, circle, very thick},
mark/.style={fill=black!50, circle},
}

\begin{document}
\begin{figure}
\begin{tikzpicture}[]
\graph [simple, edges={thick}, clockwise] {

(A 5)[mark] --[red] (A 4)[mark],
A 1 -- B a,
A 2 -- B b,
A 3 -- B c,
A 4 -- B d,
A 5 -- B e,
B a -- B c,
B a -- B d,
B b -- B e,
B b -- B d,
B e -- B c
};

\end{tikzpicture}
\end{figure}
\end{document}


I expect, that nodes 4 and 5 will be gray, but I have only red edge.

What did I do wrong?

• your code is not compileable ! – AndréC Mar 5 '19 at 20:06
• \tikzset be before \begin{document}, and \begin{tikzpicture}[] in right place. – Michail Golunyatnikov Mar 5 '19 at 20:08
• Modify your question by clicking on the edit button. – AndréC Mar 5 '19 at 20:09
• In my opinion, this is a bug in the graphs.standard library, I tried in vain to apply a style to the graphs in this library. It does not work. Let's wait and see what other TikZ users think about it. – AndréC Mar 5 '19 at 21:42
• You can not change the color of existing node. The node (A 5) is created in the subgraph command before you try to apply [mark] to it. Check TikZ 3.0: Colorate a specific node in a subgraph. – Kpym Mar 5 '19 at 22:29

I followed the link given by @Kpym in his commentary and adapted the solution given by hftf.

\documentclass[tikz,border=5mm]{standalone}

%\usepackage{tikz}
%\usepackage{caption}
\usepackage{graphicx}

\usetikzlibrary{graphs}
\usetikzlibrary{graphs.standard}

\tikzset{
every node/.style={draw, circle, very thick},
marko/.style={fill=cyan!50, circle},
}

\begin{document}
%   \begin{figure}
\begin{tikzpicture}[]
1;2;3;4[marko];5[marko];

(A 5) --[blue] (A 4),
A 1 -- B a,
A 2 -- B b,
A 3 -- B c,
A 4 -- B d,
A 5 -- B e,
B a -- B c,
B a -- B d,
B b -- B e,
B b -- B d,
B e -- B c
};

\end{tikzpicture}
%
%        \tikz
%\graph [nodes={draw, circle}, n=5, radius=1.5cm, clockwise]
%{ 1; 2; 3[fill=gray]; 4; 5; subgraph K_n };
%  \end{figure}
\end{document}