When evolution is run under KDE the color scheme is not good; the color of the selected message is barely different from that of unselected messages.  Various themes (available from System Settings->Application Appearance->GTK+ Appearance) produce various color schemes.  The one I like best is Adwaita, whose color scheme I like but whose widgets are less attractive than the ones in the default theme oxygen-gtk.  So...

I copied the oxygen-gtk theme into my local folder (~/.local), where GTK+ Appearance finds it and edited gtkrc to look like Adwaita's so far as colors go.  The key part of the edited file appears at the bottom of this posting.  I enabled it using GTK+ Appearance; unfortunately there's no change in the color scheme.  What have I done wrong?

...
# Edited by Jonathan Ryshpan on Thu Sep 18 PDT 2014
# to use the color scheme from the Adwaita theme.

# The following method is deprecated and reportedly no longer functions.
# gtk-color-scheme        = "base_color:#FFFFFF\nfg_color:#000000\ntooltip_fg_color:#FFFFFF\nselected_bg_color:#4A90D9\nselected_fg_color:#FFFFFF\ntext_color:#313739\nbg_color:#EDEDED\ninsensitive_bg_color:#F4F4F2\ntooltip_bg_color:#343434"


# oxygen's generic style options
style "oxygen-default"
{

# Colors

    bg[NORMAL]              = #4A90D9
    bg[PRELIGHT]            = shade (1.02, #4A90D9)
    bg[SELECTED]            = #4A90D9
    bg[INSENSITIVE]         = #4A90D9
    bg[ACTIVE]              = shade (0.9, #4A90D9)

    fg[NORMAL]              = #313739
    fg[PRELIGHT]            = #FFFFFF
    fg[SELECTED]            = #4A90D9
    fg[INSENSITIVE]         = darker (#4A90D9)
    fg[ACTIVE]              = #FFFFFF

    text[NORMAL]            = #313739
    text[PRELIGHT]          = #313739
    text[SELECTED]          = #4A90D9
    text[INSENSITIVE]       = darker (#4A90D9)
    text[ACTIVE]            = #4A90D9

    base[NORMAL]            = #FFFFFF
    base[PRELIGHT]          = shade (0.95, #4A90D9)
    base[SELECTED]          = #4A90D9
    base[INSENSITIVE]       = #4A90D9
    base[ACTIVE]            = shade (0.9, #4A90D9)

# Original text resumes
...