Gtk-4: Add initial suppport to gtk v4

gtk-4.0/apps/_xfce.scss

@@ -0,0 +1,107 @@
+// Xfce Panel
+.xfce4-panel.panel {
+    background-color: $panel_bg_color;
+  
+    text-shadow: none;
+    -gtk-icon-shadow: none;
+  
+    button.flat { @extend %panelbutton; }
+  }
+  
+  #tasklist-button {
+    color: transparentize($panel_fg_color, 0.2);
+    border-radius: 0;
+    border: none;
+    background-color: transparentize($panel_bg_color, 1);
+  
+    &:hover {
+      color: lighten($panel_fg_color, 10%);
+      background-color: transparentize(black, 0.83);
+    }
+  
+    &:checked {
+      color: white;
+      background-color: transparentize(black, 0.75);
+      box-shadow: inset 0 -2px $selected_bg_color;
+    }
+  }
+  
+  %panelbutton {
+    color: $panel_fg_color;
+    border-radius: 0;
+    border: none;
+    background-color: transparentize($panel_bg_color, 1);
+  
+    &:hover {
+      border: none;
+      background-color: lighten($panel_bg_color, 10%);
+    }
+    &:active, &:checked {
+      color: $selected_fg_color;
+      border-bottom: 2px solid $selected_bg_color;
+      background-color: lighten($panel_bg_color, 5%);
+  
+      label, image { color: inherit; }
+    }
+  }
+
+
+
+#whiskermenu-window button {
+    background-color:transparent;
+    border: none;
+    border-radius: 0;
+    font-weight: normal;
+    padding: 2px;
+    margin: 1px 0px;
+    &:hover, &:checked {
+        background-color: $selected_bg_color;
+    }
+}
+
+/* thunar */
+.thunar toolbar {
+  background-color: $headerbar_color; 
+}
+
+/* buttons in toolbar */
+.thunar toolbar.horizontal button image {
+  -gtk-icon-transform:scale(0.72);
+}
+
+scrolledwindow.sidebar treeview.view {
+  background: darken($_sidebar_color, 2%);
+  padding: 1.5px;
+}
+
+/* path-bar of thunar */
+window.thunar toolbar#location-toolbar > toolitem > widget > widget.linked.path-bar > button.toggle.path-bar-button, .thunar toolbar .path-bar-button {
+  margin-top: 7px;
+  margin-bottom: 7px;
+  &:hover { color: $selected_bg_color; }
+  &:checked { @include button(active-header); }
+}
+
+window.thunar toolbar#location-toolbar > toolitem > widget > widget.linked.path-bar > button.path-bar-button, .thunar toolbar .path-bar-button {
+  background: none;
+  outline: none;
+  border: none;
+  box-shadow: none;
+}
+
+/* thunar sidepane */
+window.thunar paned > scrolledwindow treeview.view {
+
+  &:hover {
+    background: darken($_sidebar_color, 3%);
+  }
+  &:selected {
+    @include button(active-header);
+    border-radius: 0;
+    box-shadow: none;
+  }
+}
+
+window.thunar toolbar#location-toolbar entry {
+  border-radius: 10px;
+}