Paste in markdown file should remove CSS

[liufengyun]

When I paste something, by default it keeps the CSS style, which is usually not what a markdown writer wants

[MikaelMayer]

Thanks for reporting. That's a broad issue of the default mode of contenteditable elements.
I think I should implement something to sanitize pasted content, e.g.
https://stackoverflow.com/questions/51758564/paste-fix-for-contenteditable

and removing extra style attributes that would be redundant.
I'm still figuring out the balance between what needs to be sanitized and what does not need to be sanitized.