How to darken the grid lines?

The grid lines on “Display Grid” in the DRAWING option, are too faint for me. The grid lines need to be considerably darker. Please can anyone help?
Many thanks!

Grid lines are displayed as a color. This can be changed from the menu Tools->Options (Preferences for Mac). Then under LibreOffice Application Colors Then in right hand pane scroll down to Draw/Presentation. There is the Grid color choice.