Created attachment 345406 [details] [review]
Allow themes to set a bg and fg color for vte-terminal

I don't know for what reason you forced vte291 to use a white bg with black fg color at this lines.
https://git.gnome.org/browse/vte/tree/src/vtegtk.cc#n1489

       gtk_css_provider_load_from_data (GTK_CSS_PROVIDER (klass->priv->style_provider),
                                         "VteTerminal, " VTE_TERMINAL_CSS_NAME " {\n"
                                         "padding: 1px 1px 1px 1px;\n"
                                         "background-color: @theme_base_color;\n"
                                         "color: @theme_fg_color;\n"
                                         "}\n",
                                         -1, NULL);

Why not using GTK_STYLE_PROVIDER_PRIORITY_THEME for background-color and color?
In result gnome-terminal or mate-terminal use your proposed colors if nothing is set in gtk+ theme or can use a theme setting if available in themes.
Ie. https://github.com/mate-desktop/mate-themes/blob/master/desktop-themes/Blue-Submarine/gtk-3.0/mate-applications.css#L897
The attached patch do exactly this and padding settings use GTK_STYLE_PROVIDER_PRIORITY_APPLICATION.

Thank you