Thank you for the plugin -- very ambitious project!!
I have been trying it out and discovered that there is a conflict with the Advanced Custom Fields plugin, which is a very popular plugin that allows you to add custom metaboxes to the edit screens.
When you add a description for your metabox, the description looks really messed up with the dark gray background: http://cl.ly/image/20430x0Z3p2c
The text also does not wrap: http://cl.ly/image/0D2c0i2V2w3F
This is because the description uses a "label" tag, and all labels have this style applied to it. I would contribute a code fix with a more specific selector, but I'm not sure which labels you want to target with this dark gray background/nowrap text.
Added more icons, fixes #4
Hi @aristath -- this looks much better. However, I'm still seeing the nowrap problem:
additional fix for #4
Got it... should work fine now. :)