\RenewDocumentCommand\qedsymbol{}{\ensuremath{\text{\textit{O.}}~\epsilon.~\delta.}}
% \renewcommand\qedsymbol{\dots}

\theoremstyle{definition}


\declaretheoremstyle[
	headfont=\bfseries\sffamily\color{NavyBlue!80},
	bodyfont=\normalfont,
	headpunct={:\\},
	qed=\qedsymbol,
	mdframed={
			linewidth=2pt,
			rightline=false, topline=false, bottomline=false,
			linecolor=NavyBlue, backgroundcolor=NavyBlue!5,
		},
]{thmexample}
\declaretheorem[numbered=no, style=thmexample,name=Beispiel]{eg}

\declaretheoremstyle[
	headfont=\bfseries\sffamily\color{RawSienna!80},
	bodyfont=\normalfont,
	headpunct={:\\},
	qed=\qedsymbol,
	mdframed={
			linewidth=2pt,
			rightline=false, topline=false, bottomline=false,
			linecolor=RawSienna, backgroundcolor=RawSienna!5,
		},
]{thmexercise}
\declaretheorem[numbered=no, style=thmexercise, name=Aufgabe]{ex}


\declaretheoremstyle[
	headfont=\bfseries\sffamily\color{ForestGreen!80},
	bodyfont=\normalfont,
	headpunct={:\\},
	qed=\qedsymbol,
	mdframed={
			linewidth=2pt,
			rightline=false, topline=false, bottomline=false,
			linecolor=ForestGreen, backgroundcolor=ForestGreen!5,
		},
]{thmdef}
\declaretheorem[numbered=yes, style=thmdef, name=Definition]{definition}

\declaretheoremstyle[
	headfont=\bfseries\sffamily\color{RawSienna!70!black},
	bodyfont=\normalfont,
	headpunct={:\\},
	qed=\qedsymbol,
	mdframed={
			linewidth=2pt,
			leftline=false, rightline=true, topline=false, bottomline=false,
			linecolor=RawSienna, backgroundcolor=Red!5,
		}
]{thmtheorem}
\declaretheorem[numbered=yes, style=thmtheorem, name=Satz]{theorem}


\declaretheoremstyle[
	headfont=\bfseries\sffamily\color{Violet!80},
	bodyfont=\normalfont,
	headpunct={:\\},
	notebraces={f\"ur }{},
	qed=\qedsymbol,
	mdframed={
			linewidth=2pt,
			rightline=false, topline=false, bottomline=false,
			linecolor=Violet, backgroundcolor=Violet!5,
		},
]{thmsolution}
\makeatletter
\@ifclasswith{report}{nosolutions}
{%
	\NewEnviron{solution}[1][]{Eine L\"osung mit dem Name ("L\"osung für #1") wurde ausgeblendet.\ \\ \par}
	\newcommand\hdsolution[1]{L\"osung ausgeblendet}
}{%
	\declaretheorem[numbered=no, style=thmsolution, name=L\"osung]{replacementSolution}

	\NewEnviron{solution}[1][]{
		\vspace{-1em}
		\begin{replacementSolution}[#1]
			\
			\BODY
		\end{replacementSolution}
	}
	\newcommand\hdsolution[1]{#1}
}
\makeatother