Tikz - How not style nodes

Question

New to using Tikz, i created tikz pictures I'd like to include in my latex document but latex keeps giving me a ! Package pgfkeys Error: I do not know the key '/tikz/none' and I am going to ignore it. error because I don't want to color my nodes (no fill or draw color). I just wanted to make a line in my image but to make a line you need to connect two nodes so I don't really need the nodes and would prefer they stay invisible.

\begin{tikzpicture}
    \begin{pgfonlayer}{nodelayer}
        \node [style=none] (0) at (-1.5, 0) {};
        \node [style=none] (1) at (7.5, 0) {};
        \node [style=none] (2) at (-1.5, 1.75) {};
        \node [style=none] (6) at (0, 3) {};
        \node [style=none] (7) at (-0.5, 0) {};
        \node [style=none] (8) at (0, 0) {};
    \end{pgfonlayer}
    \begin{pgfonlayer}{edgelayer}
        \draw (0.center) to (1.center);
        \draw (6.center) to (8.center);
   \end{pgfonlayer}
\end{tikzpicture}

How do I get around this? I made a seperate style file as well but still didn't help.

(Note I'm using a mac app tikzit to make these things)

Answer 1

To provide an official answer to the problem. As Zarko is saying, if you do not want to add a style, do not add a style, but use none only if you have defined a style of that name. Also, if you use layers, you need to define them.

\documentclass[tikz,border=3mm]{standalone}
\begin{document}
\begin{tikzpicture}
    \pgfdeclarelayer{nodelayer} 
    \pgfdeclarelayer{edgelayer}
    \pgfsetlayers{main,nodelayer,edgelayer}
    \begin{pgfonlayer}{nodelayer}
        \node  (0) at (-1.5, 0) {};
        \node  (1) at (7.5, 0) {};
        \node  (2) at (-1.5, 1.75) {};
        \node  (6) at (0, 3) {};
        \node  (7) at (-0.5, 0) {};
        \node  (8) at (0, 0) {};
    \end{pgfonlayer}
    \begin{pgfonlayer}{edgelayer}
        \draw (0.center) to (1.center);
        \draw (6.center) to (8.center);
   \end{pgfonlayer}
\end{tikzpicture}
\end{document}

The ordering of the layers has been guessed here, a common problem when the code in the question is incomplete.