# mdframed: title and subtitle

I would need to recreate the same frame as the one proposed at this page

mdframed: Put a line below the frame title and give it a shaded background

with the only exception of adding a subtitle with a white background. For example

Klassenbildung

Subtitle with white background

Text text text

I would also need to add multiple subtitles and distribute the text on multiple pages. Any idea of how to do it?

\documentclass{article}

\usepackage[most]{tcolorbox}
\usepackage{lipsum}

\begin{document}

\begin{tcolorbox}[title={Klassenbildung},breakable,arc=0mm,outer arc=0mm,colbacktitle=lightgray!50!white,coltitle=black,colframe=gray,fonttitle=\bfseries,colback=white,subtitle style={colback=white}]
\vspace{-1.3\baselineskip}
\tcbsubtitle{Subtitle with white background}

\lipsum[2]

\tcbsubtitle{Another subtitle with white background}
\lipsum
\end{tcolorbox}

\end{document}