centering title page with sidebar https://latex.org/forum/viewtopic.php?t=23158

bar169.tex

@@ -24,5 +24,20 @@
 \usetheme{Bar169}
 
 \begin{document}
+    \begingroup
+        \makeatletter
+        \setlength{\hoffset}{.5\beamer@sidebarwidth}
+        \makeatother
+        
+        \begin{frame}[plain]
+            % Print the title page as the first slide
+            \titlepage
+        \end{frame}
+
+        \begin{frame}[plain]{Overview}
+            % Throughout your presentation, if you choose to use \section{} and \subsection{} commands, these will automatically be printed on this slide as an overview of your presentation
+            \tableofcontents
+        \end{frame}
+    \endgroup
     \input{content.tex}
 \end{document}

content.tex

@@ -1,14 +1,5 @@
 \definecolor{lightblue}{rgb}{0.67,0.87,0.9}
 
-\begin{frame}[plain]
-    % Print the title page as the first slide
-    \titlepage
-\end{frame}
-
-\begin{frame}{Overview}
-    % Throughout your presentation, if you choose to use \section{} and \subsection{} commands, these will automatically be printed on this slide as an overview of your presentation
-    \tableofcontents
-\end{frame}
 
 %------------------------------------------------
 \section{Motivation \& References}

simple.tex

@@ -25,5 +25,14 @@
 % \useoutertheme{tree}
     
 \begin{document}
+    \begin{frame}[plain]
+        % Print the title page as the first slide
+        \titlepage
+    \end{frame}
+
+    \begin{frame}[plain]{Overview}
+        % Throughout your presentation, if you choose to use \section{} and \subsection{} commands, these will automatically be printed on this slide as an overview of your presentation
+        \tableofcontents
+    \end{frame}
     \input{content.tex}
 \end{document}