[vte] widget: Improve legibility by using the appropriate background color

[Christian Persch <chpe src gnome org>]

commit a737e397e391761546dd9356ec99f499ccaa4cf8
Author: Debarshi Ray <debarshir gnome org>
Date:   Sat Aug 8 21:55:09 2020 +0200

    widget: Improve legibility by using the appropriate background color
    
    From GTK 3.24.22 onwards, Adwaita exports a text_view_bg color [1]
    that's meant to be used as the background in text views, such as
    terminal emulators, where higher contrast helps with legibility.
    
    [1] https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/2402
        https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/2403
    
    Fixes: https://gitlab.gnome.org/GNOME/vte/-/issues/226

 src/vtegtk.cc | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/src/vtegtk.cc b/src/vtegtk.cc
index 5fcae132..936b38b9 100644
--- a/src/vtegtk.cc
+++ b/src/vtegtk.cc
@@ -2023,7 +2023,11 @@ vte_terminal_class_init(VteTerminalClass *klass)
         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"
+#if GTK_CHECK_VERSION (3, 24, 22)
+                                         "background-color: @text_view_bg;\n"
+#else
                                          "background-color: @theme_base_color;\n"
+#endif
                                          "color: @theme_text_color;\n"
                                          "}\n",
                                          -1, NULL);