Format individual columns in a datatable

[mikey]

thanks @al_mostafa_nahas and @ayoub

1. the docs should probably get an update with this sort of helpful info, for those of us who aren’t native web devs.
2. while the change to the header works in studio, it does not seem to work in preview.
   css:

self .col-selected > span , self .header-selected {
	text-align:center;
}

studio:

preview: