Theme Starter theme does not fix dark body view like the builtin dark theme

Development Themes Development
#1

Description

All the dark themes I found here, had poorer rendering of the message body than the builtin Dark theme. So I cloned the Mailspring-Theme-Starter and made my own. I found out that this starter has the same issue as I’m trying to avoid: Parts or whole of email bodies are rendered bright.

Screenshots

Example from the builtin dark theme, an Mac App Store receipt email body:

Builtin Dark
Builtin Dark502×564 57.9 KB

And this built on Mailspring Theme Starter (just changed primary color from green to blue):

Theme Starter
Theme Starter564×576 60.5 KB

I tried finding the builtin theme to copy from that, but I haven’t located where it’s stored.(?)

Install

I haven’t uploaded my own anywhere, all I did was to git clone this:

And then I changed the primary color from green to blue (as you see in the bright screenshot above).

So, does anyone know how to either find the builtin Dark theme, so I can steal from that, or how to get the same, nice and dark, message body?

(Edit: Changed it from the Themes category to development: themes …)

Edit 2: I found this:

And following the link to the mentioned Dark vs. Starter theme GitHub issue, I’ve been able to start to get good results, by adding a file email-frame.less with this content:

.ignore-in-parent-frame {
  body {
    -webkit-filter: invert() hue-rotate(180deg);
    color: #111;
  }
  img {
    -webkit-filter: invert() hue-rotate(180deg);
  }
}

… And also removing the index.less file.