Use dark mode for code preview if user prefers `prefers-color-scheme: dark`

pystencils currently does not look good in dark mode :/

pystencils/display_utils.py

@@ -30,7 +30,10 @@ def highlight_cpp(code: str):
     from pygments.lexers import CppLexer
 
     css = HtmlFormatter().get_style_defs('.highlight')
-    css_tag = "<style>{css}</style>".format(css=css)
+    dark_css = HtmlFormatter(style="stata-dark").get_style_defs('.highlight')
+
+    css_tag = "<style>{css} @media (prefers-color-scheme: dark) {{ {dark_css} }}</style>".format(css=css,
+                                                                                                 dark_css=dark_css)
     display(HTML(css_tag))
     return HTML(highlight(code, CppLexer(), HtmlFormatter()))