Gnumeric problem

Gnumeric doesn’t have an option to set the grid to dark colors, which can cause readability issues for people with vision problems when using light themes.

Procedure

1. Open Gnumeric’s CSS stylesheet with a text editor:

Linux:

$HOME/.config/gtk-3.0/gtk.css

Windows:

C:\Users\YourUser\AppData\Roaming\gtk-3.0\gtk.css

At the end of the file, add the following:

/* Cell background */ 
GnmItemGrid,
GnmPreviewGrid,
GocCanvas {
	background-image: none;
	background-color: #1A1A1A; /* Choose your desired background color */ 
	color: #91a666;
	padding: 0;
	border-style: none;
	border-width: 0;
}

/* Cell borders */

GnmItemGrid.grid,
GnmPreviewGrid.grid {
	color: #a6a6a6;
}

/* Cursor (selected cell) */
GnmItemCursor.normal {
  color: #eeeeee;
}

/* Colors when editing a cell directly */
GnmItemEdit {
  background-color: #3a3a3a;

  /* This doesn't seem to kick in. We seem to get the color from the
     style. */
  color: #a6a6a6;
}

/* Entire column/row selected */
button:active.itembar, button:active.itembar * {
    color: white;
    font-weight: bold;
}

/* Partial column/row selection */
button:hover.itembar, button:hover.itembar * {
  color: white;
  font-weight: bold;
}

With this, GTK3 will override several interface values in Gnumeric. Thanks to the fact that Gnumeric has independent internal components, these changes do not affect other GTK3-based programs.

Text Color

The only issue I couldn’t solve is the text color. No matter what I changed, the text remained black. So the only workaround with this method is to select all the cells in the document and set their text color to white. If anyone knows a solution, please let me know as an issue