Changes

'''New''': This and the following definitions don't work with recent (mkIV) versions of context. Instead, use <texcode>\define[2]\YourCommand{\framed[frame=off, etc...code as before}</texcode> '''Section titles'''. Red numbers and black title on top of a gray background. The problem was long titles: how to get the text properly aligned (if you don't do anything, the text of the second line will be left-aligned, under the section number). The solution was provided by Wolfgang Schuster(but see "New" above):

'''Subsections'''. "sans serif" on a gray background, but no numbering. The publisher wanted some distance between the left and the beginning of the subsection text, so I used Wolfgang's trick again(but see "New" above):