Using the Ajax Theme Studio 
Use the Ajax Theme Studio to create new themes by changing the leading color of the SAP Tradeshow theme. You can then fine-tune the new theme in the Theme Editor.
Go to .
Select one of the colors and choose Preview.
The Preview window displays the effect that the color change has on the theme.
When you have decided on a color, choose Done.
Specify a name for the theme and choose Export.
Note
The theme name can only contain alphanumeric characters and spaces, and must not begin with SAP.
Save the compressed file on your machine.
Use the Transport Themes tool to import the theme into the portal.