Add midnight-ocean color scheme support for GTK2/3/4 and Qt5/6

.config/gtk-4.0/colors.css

@@ -0,0 +1,39 @@
+/* midnight-ocean GTK4 overrides */
+
+@define-color theme_bg          rgba(11, 27, 43,   0.98);
+@define-color theme_fg          rgba(202,211,232,  0.90);
+@define-color theme_selected_bg rgba(79,132,204,   0.30);
+@define-color theme_hover_bg    rgba(79,132,204,   0.50);
+@define-color theme_border      rgba(79,132,204,   0.50);
+@define-color theme_accent      #4F84CC;
+@define-color theme_warning     #FFCC33;
+
+window,
+dialog,
+headerbar {
+  background-color: @theme_bg;
+  color: @theme_fg;
+}
+
+selection,
+row:selected,
+button:checked,
+switch:checked {
+  background-color: @theme_selected_bg;
+  color: @theme_fg;
+}
+
+button:hover,
+entry:hover,
+scrollbar:hover {
+  background-color: @theme_hover_bg;
+}
+
+*:focus {
+  outline: 1px solid @theme_accent;
+}
+
+.error {
+  background-color: @theme_warning;
+  color: @theme_bg;
+}