[Bug] Summary.mht file has messed up tables

[Smurf-IV]

Describe the bug

To Reproduce
Using Release 5.4.15 via command line

[danielpalme]

The problem is, that the CSS file embedded into to the MHTML is not used by modern browsers.
I fixed this in release 5.4.16 by inlining the CSS into the HTML files.
Disadvantage: The MHTML file gets bigger.

I consider dropping this format in future release completely.
In the past this format was great to place all HTML, CSS and JavaScript content into a single file.
Now it basically the same as HtmlSummary. You are no longer able to navigate to the details pages, JavaScript is blocked.

[Smurf-IV]

Can confirm that the Tables have colours and borders etc.