Customize gtkrc theme xfce-flat

If you're using Thunar, you can change the side-pane's color by editing a file called thunar.rc. Its location depends on where your theme is. I like to have my themes in ~/.themes and so my thunar.rc has this filepath: /home/dkb/.themes/MyGreybird/gtk-2.0/apps/thunar.rc.

In my thunar.rc, right at the top, I have:

style "sidepane"
{
    GtkTreeView::vertical-separator = 4

    base[NORMAL]        = @link_color
    base[INSENSITIVE]   = mix (0.4, shade (1.35,@selected_bg_color), shade (0.9,@base_color))

    text[NORMAL]        = mix (0.7, @text_color, @base_color)
    text[ACTIVE]        = mix (0.7, @text_color, @base_color)
    text[SELECTED]      = mix (0.7, @text_color, @base_color)

When I have

base[NORMAL]        = @link_color

Thunar's side-pane looks like this:

When I have

base[NORMAL]        = mix (0.1, shade (1.35,@selected_bg_color), shade (0.9,@base_color))

Thunar's side-pane looks like this:

@link_color, @selected_bg_color, and @base_color are defined in your theme's gtkrc. In my case, the filepath is this: /home/dkb/.themes/MyGreybird/gtk-2.0/gtkrc.

You can define your own color in gtkrc by just adding to the list of defined colors:

For example, you may have:

gtk-color-scheme    = "bg_color:#777777\nselected_bg_color:#398ee7\nbase_color:#666666" # Background, base.
gtk-color-scheme    = "fg_color:#3C3C3C\nselected_fg_color:#ffffff\ntext_color:#212121" # Foreground, text.
gtk-color-scheme    = "tooltip_bg_color:#000000\ntooltip_fg_color:#E1E1E1" # Tooltips.
gtk-color-scheme    = "link_color:#2d71b8" # Hyperlinks
gtk-color-scheme    = "panel_bg:#686868" # Panel bg color
gtk-color-scheme    = "fm_color:#F7F7F7" # Color used in Nautilus and Thunar.
gtk-color-scheme    = "bg_color_dark:#686868\ntext_color_dark:#FFF"

Then just add something like:

gtk-color-scheme    = "my_thunar_sidepane_color:#2c2c2c"

if you want to match the color of the main pane, for example. Save gtkrc and modify thunar.rc to use your defined color and reload your theme. When you next open Thunar, it should reflect the change you made.