I like Preview Pane option very much (it is from Lab section: https://gmail.googleblog.com/2011/08/new-in-labs-preview-pane.html). But the look of message list in vertical preview mode is not very good for perception as for me: text lines are glued together, margins are too small, message sender's name has the same font as title and content snippet.

My style is trying to fix given hardship.

For thus who are using non-deafult color scheme (or just want to play with options) some of style's colors can be altered when installing/updating the style (see fields above).

This style is intended to be used with vertical Preview Pane mode. If other mode is activated the result will be quite poor (but still usable).