gtk4: Add libadwaita public color definitions

Author: jnsh

common/gtk-4.0/sass/_libadwaita-defaults.scss

@@ -0,0 +1,61 @@
+/* GTK NAMED COLORS
+   ----------------
+   use responsibly! */
+
+// Sass thinks we're using the colors in the variables as strings and may shoot
+// warning, it's innocuous and can be defeated by using #{$var}.
+
+// These are the colors apps are can override. 
+// Derived from src/stylesheet/_defaults.scss in libadwaita source tree.
+
+// The main accent color and the matching text value
+@define-color accent_bg_color #{$selected_bg_color};
+@define-color accent_fg_color #{$selected_fg_color};
+@define-color accent_color #{$selected_bg_color};
+
+// destructive-action buttons
+@define-color destructive_bg_color #{$destructive_color};
+@define-color destructive_fg_color #{$destructive_fg_color};
+@define-color destructive_color #{$destructive_color};
+
+// Levelbars, entries, labels and infobars. These don't need text colors
+@define-color success_bg_color #{$success_color};
+@define-color success_fg_color white;
+@define-color success_color #{$success_color};
+
+@define-color warning_bg_color #{$warning_color};
+@define-color warning_fg_color #{$warning_fg_color};
+@define-color warning_color #{$warning_color};
+
+@define-color error_bg_color #{$error_color};
+@define-color error_fg_color #{$error_fg_color};
+@define-color error_color #{$error_color};
+
+// Window
+@define-color window_bg_color #{$base_color};
+@define-color window_fg_color #{$text_color};
+
+// Views - e.g. text view or tree view
+@define-color view_bg_color #{$bg_color};
+@define-color view_fg_color #{$fg_color};
+
+// Header bar, search bar, tab bar
+@define-color headerbar_bg_color #{$header_bg};
+@define-color headerbar_fg_color #{$header_fg};
+@define-color headerbar_border_color #{$header_border};
+@define-color headerbar_backdrop_color #{$header_bg_backdrop};
+@define-color headerbar_shade_color #{$bg_color};
+
+// Cards, boxed lists
+@define-color card_bg_color #{$base_color};
+@define-color card_fg_color #{$fg_color};
+@define-color card_shade_color #{$base_color};
+
+// Popovers
+@define-color popover_bg_color #{if($variant!='dark', $base_color, $bg_color)};
+@define-color popover_fg_color #{$fg_color};
+
+// Miscellaneous
+@define-color shade_color #{transparentize(black, 0.8)};
+@define-color scrollbar_outline_color #{if($variant != 'dark', white, transparentize(black, .5))};
+

common/gtk-4.0/sass/gtk.scss.in

@@ -6,3 +6,4 @@ $transparency: '@transparency@';
 @import "@sass_path@/_common";
 @import "@sass_path@/_colors-public";
 @import "@sass_path@/_libadwaita";
+@import "@sass_path@/_libadwaita-defaults";