CSS Test: Column-width applied to 'display: table-header-group'

Test passes if there is no red visible on the page.

AAAAAAAAA BBBBBBBBB CCCCCCCCC DDDDDDDDD EEEEEEEEE FFFFFFFFF GGGGGGGGG HHHHHHHHH IIIIIIIII JJJJJJJJJ KKKKKKKKK LLLLLLLLL