Comment 6 for bug 1050551

The easy and quick fix is to swap the tooltip-fg and tooltip-bg colors.
The tooltips then have dark background and are not ideally distinguishable from the rest of the UI, but at least they're readable :)

## gtk.css
@define-color tooltip_bg_color #333333;
@define-color tooltip_fg_color #fffde0;

## settings.ini
gtk-color-scheme = "base_color:#686868\nbg_color:#444444\ntooltip_bg_color:#333333\nselected_bg_color:#9db6cd\ntext_color:#efefef\nfg_color:#efefef\ntooltip_fg_color:#FFFDE0\nselected_fg_color:#F5F5F5\nlink_color:#74a0c6\nbg_color_dark:#686868\nfg_color_dark:#fcfcfc"