In my case, i am development for mobile devices (tablet like ,example : IPAD). Zk is beautiful but in mobile devices is most important the performance.

A minimum theme could be:

• White base color (my corporate color is green but in some places i forget change the default blue to green).
• Reduce or disable js effects (great work with the option to disable the borderlayout animations)
• Reduce (or delete) the number of images in the themes. (A lot of micro images to render some component)

Optional:

• Optimice and reduce css, don't use slow code.

Thanks, the market goes towards the mobile devices and zk will go step further.