To change Gridline color in Excel, use Excel Options, apply a custom-colored border to the cells, or apply a custom line color. Full details here.

I have a set of spreadsheets where the data (text) is color-coded by row. Would it be feasible to write a formula or script to count how many of what color rows are spread across the workbooks in ...

This tutorial will show you how to change the default Color, Shape, and Font of a Comment Box in Excel the easy way.