Ask your DiL to be if there are any colours she would prefer you to avoid then find something you like and buy it. You can't please everyone online because you will have the you can wear literally any colour other than white, oh and any pale colour that might look white or whitish in photos, and red or green or black or any dark colour that might look black and now we have or blue. The pattern phobes will insist you must wear a block colour, the modern minimalists will say it has to be an over size shapeless sack, the traditionalists will say it has to be something my granny would have worn in the 80s and so on and so forth. Wear what you like and feel good in and enjoy the day.