How change portal application(WD) background color

Hi,

We upgrade the portal from 7 to 7.31.

In portal 7 I could change the portal applications background from the theme editor ( WD pages that running under sap portal)

In 7.31 I cannot find in the theme editor the property.

By default the background color is blue, I want to change it to white.

How can I do it from the theme editor ?

Is there another way like edit some css file ?

Thank,

Faniel