CSS improvements for better layout on any window size

[denilsonsa]

• The inner scrollbar is now visible, because the fixed blue box now fits the page width.
• The height is never greater than 90% of the window height.
• The title is now clickable, and points back to the repository (just in case people forget they have this user-script installed). (Also, technically this is not a CSS change.)

[RyanBluth]

Thanks, looks good