I used Hal's version of the Riot Chat CSS as a base for this version. I tweaked a few things to be used for people who want to keep Riot Chat in a separate window.

Changes That I Made:
Shrunk the size of the topic and time stamp.
(So you can make your window smaller with out having the topic wordwrap...)

Hide the user avatars across the entire window.
(because chalkley3's avatar is very very annoying.

Shrunk the size of the text it self to 12px.
(but I have mine at 10px because screw you guys I like it smaller)

Removed the padding on the left, right and top.
(For obvious reasons)

Removed the input button and expanded the size of the input box.
(If you're confused just hit "return" to send a message)

Removed the right side menu bar.
(Because it can be assumed you don't want it there..)

Tweaked the width of the user box and the conversation box.
(To make room for the new mouse over effect)