Ubuntu – How to get rid of white color on white text for Ambiance Blue theme

After upgrading to Ubuntu 12.04, windows pop up with white color on white text. I am lost, confused, feeling very stupid and am not sure what to do next. I would greatly appreciate it if someone could please take a look at my issue.

My problem is similar to this person's experience:

Hope-DT GTK+ theme displays white fonts after upgrade to 12.04

I see on advanced settings I am using the 'Ambiance Blue' GTK+ theme, whatever a GTK+ is. Changing this to any of the other GTK+ themes fixes the white on white problem, but makes the background colours of minimised windows really ugly – i.e. like graphics of early 1980s PCs. Only 'Ambiance Blue' seems to set them right.

Looking at White text on white background problem,
it seems I need to manually edit some configuration files. There's 3 configuration files and I didn't know which one to use, so I changed them all. Now I have:

**/usr/share/themes/Ambiance Blue/gtk-3.0/gtk.css:**

/* default color scheme */
@define-color bg_color #cdc3b8;  
@define-color fg_color #262626;  
@define-color base_color #accdff;  
@define-color text_color #262626;  
@define-color selected_bg_color #01b9fc;  
@define-color selected_fg_color #ffffff;  
@define-color tooltip_bg_color #A3D0FF;  
@define-color tooltip_fg_color #023C79;

**/usr/share/themes/Ambiance Blue/gtk-3.0/settings.ini:**

    [Settings]
gtk-color-scheme = "base_color:#accdff\nbg_color:#cdc3b8\ntooltip_bg_color:#a3d0ff\nselected_bg_color:#ffffff\ntext_color:#262626\nfg_color:#262626\ntooltip_fg_color:#023c79\nselected_fg_color:#ffffff\nlink_color:#1448dd\nbg_color_dark:#373b3c\nfg_color_dark:#d2dbdf"

**/usr/share/themes/Ambiance Blue/gtk-2.0/gtkrc:**


gtk-color-scheme = "base_color:#accdff\nfg_color:#262626\ntooltip_fg_color:#023c79\nselected_bg_color:#01b9fc\nselected_fg_color:#ffffff\ntext_color:#262626\nbg_color:#cdc3b8\ntooltip_bg_color:#a3d0ff\nlink_color:#1448dd"

I restart the computer and then go into advanced settings and select 'Ambiance Blue' and I still get white on white.

Q1. Which of the 3 configuration files actually matters?

I am not using unity; I'm not sure what I'm using. Gnome 2 or gnome 3 or gnome-something or something like that I think. Here are some environment variables:

GTK_MODULES=canberra-gtk-module:canberra-gtk-module
XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session0
XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0
DEFAULTS_PATH=/usr/share/gconf/gnome-classic.default.path
XDG_CONFIG_DIRS=/etc/xdg/xdg-gnome-classic:/etc/xdg
DESKTOP_SESSION=gnome-classic
MANDATORY_PATH=/usr/share/gconf/gnome-classic.mandatory.path
GDMSESSION=gnome-classic
GNOME_DESKTOP_SESSION_ID=this-is-deprecated
XDG_DATA_DIRS=/usr/share/gnome-classic:/usr/share/gnome:/usr/local/share/:/usr/share/
XDG_CURRENT_DESKTOP=GNOME

Q2. Is there some way of testing this without restarting the computer each time? (I tried turning all numbers in one of the files to #000000 but it didn't seem to do anything.

Q3. Exactly which number do I need to change to get rid of the white-on-white?