ExtJS + CSS Expert needed

Please take a look at the attached image. We've got a grid (using simply a standard ExtJS grid) which has to be styled a bit. Your job is: to style the grid as needed using CSS, and to add the black border to left and right and a bit to top and bottom (maybe using some empy panels with custom flex params (?) as the border shall vary according to browser size). Please provide some example of your ExtJS experience. Please mention "extjsgridcss" in your application. If everythings works fine, we've got lots more to ;-) You get the whole application from us, so there is no need for programming Javascript/ExtJS (except maybe the addtional black panels of course).