Set default font to tikz flowchart

Question

I am a beginner with latex and tikz, and am using a .sty template to set my default fonts etc throughout the document (university requirement). This makes all the default text slightly larger than usual and adds 1.5 line spacing.

However I would like to add a flowchart (which I built successfully in a separate latex file using tikz). The problem is that once I pasted the code into the other document (the one with the template), the text inside the flowchart changed to that document's default (larger and with 1.5 line spacing). Obviously this made all the process boxes of the flowchart larger and they no longer fit in a page. Is there a way to only change the font of the tikz shapes to the latex default? I found ways how to add line spacing to the tikz shapes, or change the font, but cannot find how to set it to the latex default (which is not the default of that document).

Thanks. Your help is greatly appreciated.

Answer 1

A small extension of cfr's comment:

\documentclass[17pt]{extarticle}
\usepackage[doublespacing]{setspace}
\usepackage{tikz}
\usepackage{kantlipsum}
\begin{document}
\kant[1]
\begin{tikzpicture}[every node/.style={font=\small\singlespacing}]
\node [text width=12cm] {\kant[1]};
\end{tikzpicture}

\kant[3]
\end{document}

Answer 2

...
\usepackage[doublespacing]{setspace}
...
\begin{tikzpicture}
\node {\parbox{12cm}{\small\singlespacing\kant[1]}};
\end{tikzpicture}