Edit 15.7.2023 Old instruction does not work anymore, but the solution can found from Mint forums.

https://forums.linuxmint.com/viewtopic.php?t=368175

xdg-open ~/.config/gtk-3.0/gtk.css

.nemo-window .view, .nemo-window iconview {
background-color: #E4FFC9;
color: #000000;
}
.nemo-window .nemo-inactive-pane .view, .nemo-window .nemo-inactive-pane iconview {
background-color: #FFFFFF;
color: #000000;
}
.nemo-window .sidebar .view {
background-color: #5C6A4D;
color: #FFFFFF;
}

########################################################
If you do not like the Nemo’s default backgroud color, the color can change at least the next way:

Make a ~/.config/gtk-3.0/gtk.css file.

nano ~/.config/gtk-3.0/gtk.css

… the contents

.nemo-desktop.nemo-canvas-item {
color: #ffffff;
}

.nemo-desktop.nemo-canvas-item:selected {
background-color: alpha (#e0d963, 0.2);
}

NemoWindow .sidebar, NemoWindow .sidebar .view {
background-color: #444;
color: #eee; /* light grey */
}

NemoWindow .view {
background-color: #76ecd7;
color: #0d0c0c;
}

… the fist lines are optitional and crucials lines are

NemoWindow .view {
background-color: #76ecd7;
color: #0d0c0c;
}

After editing save, quit and logout and login.

 

 

 

 

 

 

 

 

 

 

 

 

 

If wanting to restore default colors, just delete ~/.config/gtk-3.0/gtk.css file.

For choosing a good color, GIMP’s colorchooser is a good tool.