Use native GTK grid lines (or at least something thinner)
Bug Summary
For the conversation list, renders its own separators using cairo strokes which results in very thick lines whose color doesn't match the surrounding lines:
These are thicker than any line I can find in any gnome app, and thus feel out of place. Here's what it looks like with the native GTK grid lines.
Unfortunately those grid lines might be classified as overly thin, but they are at least the norm across gnome apps.
I tried modifying the cairo rendering in FormattedConversationData
but fractional stroke widths only lightened the border, but didn't thin it out (presumably because of some sort of anti-aliasing behavior).
Anyway, this seems like something that should follow the default platform behavior and I'm happy to post a MR but I wanted to ask the maintainers how you feel about it before posting a surprise UI-modified MR.