Changes in CSS files not reflecting in CRM Web UI

Hi,

I am trying to changed the skin of CRM Web UI.

I am editing "thtmlb_stand.css" file for the same.

I could edit background color of headercontainer in following tag:-

th-l-headercontainer

th-l-logofflink

th-l-logofflink:visited

1. But changes I made in navigation bar layout are not visible in Web UI. (Its showing same old colors)

th-menu-rootlink

th-menu-rootItemOff .th-menu-rootlink

th-menu-rootItemOn .th-menu-rootlink

th-menu-itemOn

2. Also, under headercontainer, I am seeing a horizontal gutter with alternating colors (blue, orange, red, grey, purple and green).

I want to get rid of the gutter.

How do I do it?

Please help.

Thanks and regards,

Amey