Suggestion: Option to set background color of preview window

[basvdijk]

Currently I am using the dark theme in vscode. However the transparent SVG images make it hard to read the text of the diagram on a dark background.

It would be nice if there is a setting where you can set the background window background color to white.

I can imagine one says: Then just use another theme which looks nice on a dark background. However generate documentation with a light background. Therefore it would to use the same theme when previewing.

[vstirbu]

Do you disable the automatic light/dark mode selection using the configuration mermaid.theme? Wondering if the background color configuration is always dependent on providing the theme.