fix: schematic-dark.png and schematic.png

Author: f-allian

images/schematic-dark.png

@@ -20,7 +20,7 @@
 \newcommand{\cmark}{\ding{51}}%
 \newcommand{\xmark}{\ding{55}}%
 
-\begin{tikzpicture}[background rectangle/.style={fill=black}, show background rectangle, color=white]
+\begin{tikzpicture}[background rectangle/.style={fill=none}, show background rectangle, color=black]
 
   \begin{scope}[name prefix=scenario-, local bounding box=specification]
     % Causal DAG