How to set background color of grid head row

Suite and Optimus Suite 5
#1

how to set background color of grid head row?
the second is the vertical cell border that which can not see, it is so thin, i want to config the border of the header columns and cells.

#2

You may try to use the setStyle() method:
https://docs.dhtmlx.com/api__dhtmlxgrid_setstyle.html
its’ first parameter allows changing the style of your grid header.