Power store does not offer a way for the admin to change those settings in the design editor,nor can it be added.
you need to modify the css manually to change that.
to change it in both the site and the admin design editor, edit the
webassist/themes/crazy/configurable.css
add the following style at the end:
#banner .block {
background-color:#999;
}
.ps_pod2 {
background-color:#999;
}