In the Format Data Point pane, click the "Fill and Line" paint pot, and in the Fill section, check "Solid fill," and change ...
This guide describes how to grey out unused cells in Excel in Windows 11/10, apply a solid fill color, use Conditional Formatting, or hide unused rows/columns.
When I started using Microsoft Excel, my spreadsheets were a mess, and I wasted hours trying to make them look professional.