* Calendar rewirte.

gtk-3.20/scss/widgets/_calendar.scss

@@ -7,17 +7,62 @@
         padding: $spacing;
         outline-offset: -1px;
 
-        &:indeterminate { color: mix($fg_color, $bg_color, .5); }
+        color: $text_color;
 
-        &.view, &.highlight, &.header, &.button {
-            &, &:focus, &:hover, &:disabled {
-                border: 0;
-                background-color: transparent;
-                background-image: none;
+        &.view {
+            &, &:backdrop { @extend %undecorated_button; }
+        }
+
+        &:selected {
+            @extend %selected_items;
+
+            padding: 5px;
+            border-radius: $roundness;
+        }
+
+        &.header {
+            border-bottom: 1px solid transparentize($black, .9);
+            border-radius: 0;
+
+            &:backdrop { border-color: transparentize($black, .9); }
+        }
+
+        &.button {
+            @extend %undecorated_button;
+
+            color: alpha($fg_color, .55);
+
+            &:hover {
+                @extend %undecorated_button;
+
+                color: $fg_color;
+            }
+
+            &:backdrop {
+                @extend %undecorated_button;
+
+                color: alpha($backdrop_fg_color, .55);
+            }
+
+            &:disabled {
+                @extend %undecorated_button;
+
+                color: alpha($insensitive_fg_color, .55);
             }
         }
 
-        &.highlight { color: $selected_bg_color; }
+        &:indeterminate,
+        &:indeterminate:backdrop { color: mix($fg_color, $bg_color, .5); }
+
+        &.highlight,
+        &.highlight:backdrop {
+            font-size: smaller;
+            color: $selected_bg_color;
+        }
+
+        &:backdrop {
+            color: $backdrop_text_color;
+        }
     }
 
     /* gnome-calendar */