The post image shows Tesseract in dark mode with the Dark Reader extension active. It's not supposed to look like that lol. In the SpaceX post, the text should be legible with a gradient effect, but DarkReader breaks that. Also, the borders should not be anywhere near that pronounced.
This is how it's supposed to look in native dark mode
Native light mode + Dark Reader looks kind-of okay (I may even adjust the native color scheme to be closer to that), but it still breaks the gradient effect on collapsed post previews and makes some buttons appear disabled:
You can disable Dark Reader on a per-site basis, and it's recommended to do so for Tesseract. Customizing the native themes to work better with Dark Reader is obviously not a priority since there is a native dark theme already lol.
Edit: I found there's a way for the app to tell Dark Reader to disable, and I have that added to the dev branch. I'm working on making that "disable" header dynamic, but for now, I'm fine with statically disabling it.
Does dark reader detect if you add CSS specifying that it's a dark theme? No idea if it does, but maybe something to look at.
I also thought Tesseract had some odd theming choices until I remembered I've got DR installed lol
Ok, I looked into it further, and I can actually just have the app ask Dark Reader to disable itself:
<meta name="darkreader-lock">Added that in dev, and it works.There are already CSS classes in place which say it's in "dark" theme, but DR doesn't look at those. They maintain a list of sites that are already natively dark that it will ignore, but that's impractical for a Fediverse application which can be hosted on any domain.
I hate to be heavy handed about it, but there is a dark theme already that also responds to system preference (in addition to having easy-to-reach manual toggles). There's a way to do it dynamically which I may work on, but it'll require additional testing.