app/pb_kits/playbook/pb_table/docs/_table_with_header_style_floating_rails

Further customize your header by using the table with background kit logic to give your table header a custom background color. Use the header_style: "floating" prop to visually nest the borderless table within a card or collapsible with a matching background color (the background_color passed to Background kit should match the background or background_color for the element in which it is nested).