Move #XfceNotifyWindow code to apps/_xfce.scss

src/gtk-3.0/scss/apps/_xfce.scss

@@ -23,4 +23,17 @@
 
         .menu { -gtk-image-effect: none; }
     }
+
+    #XfceNotifyWindow {
+        background-color: $osd_bg;
+        color: $osd_fg;
+        border-radius: $roundness;
+        border: 1px solid border_normal($osd_bg);
+
+        GtkLabel {
+            &#summary {
+                font-weight: bold;
+            }
+        }
+    }
 }

src/gtk-3.0/scss/widgets/_osd.scss

@@ -128,17 +128,4 @@
             background-image: none;
         }
     }
-
-    #XfceNotifyWindow {
-        background-color: $osd_bg;
-        color: $osd_fg;
-        border-radius: $roundness;
-        border: 1px solid border_normal($osd_bg);
-
-        GtkLabel {
-            &#summary {
-                font-weight: bold;
-            }
-        }
-    }
 }

src/gtk-3.20/scss/apps/_xfce.scss

@@ -27,4 +27,21 @@
             text-shadow: none;
         }
     }
+
+    #XfceNotifyWindow {
+        .osd {
+            background-color: $osd_bg;
+            color: $osd_fg;
+            border-radius: $roundness;
+            border: 1px solid border_normal($osd_bg);
+        }
+
+        &.osd {
+            label {
+                &#summary {
+                    font-weight: bold;
+                }
+            }
+        }
+    }
 }

src/gtk-3.20/scss/widgets/_osd.scss

@@ -263,21 +263,4 @@
             }
         }
     }
-
-    #XfceNotifyWindow {
-        .osd {
-            background-color: $osd_bg;
-            color: $osd_fg;
-            border-radius: $roundness;
-            border: 1px solid border_normal($osd_bg);
-        }
-
-        &.osd {
-            label {
-                &#summary {
-                    font-weight: bold;
-                }
-            }
-        }
-    }
 }