The default active cell format in Microsoft Excel isn't all that easy to see, but you can use this easy-to-implement code solution to change that.

Click Visual Basic or Alt+F11 to open your developer VBA editor. Highlight the Worksheet where you would like to run your code or select a module that contains your VBA code. Go ahead and paste the ...

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.