This style is based on the awesome work of David Willie with his style (linked below) but blends the colours in a slight more natural way (at least for me).

http://freestyler.ws/style/137785/messenger-solarized

This is my first style, and if I work it out, I'll play with the style settings to allow toggling with Solarized Light / Dark and the accent colours.

Changelog:
2017-04-17 1025AEST: Fixed bug (thanks Mitchicus for the report!) when you highlight text in chat window. Also tweaked incoming message highlights.
2017-04-17 1000AEST: Highlight incoming messages in the chat list.
2017-04-17 0500AEST: Initial theme.