calendar: Add css style for marked days

As part of a6f9052cf1c1c7b4224834ed18a63e70477d8729, marked days lost
their style, essentially making that function worthless.  Previously,
they were simply bolded, but that doesn't give them proper justice.

diff --git a/gtk/theme/Default/_common.scss b/gtk/theme/Default/_common.scss
index 056d36c8d37e2880282be266ad41d7db65de5cd1..fd25bfc0d68bfbdbd5d0a702b029e8bdc8b38fe3 100644 (file)
--- a/gtk/theme/Default/_common.scss
+++ b/gtk/theme/Default/_common.scss
@@ -3510,6 +3510,10 @@ calendar {
         @extend %selected_items;
         border-radius: 3px;
       }
+
+      &:checked {
+        background-color: gtkalpha($selected_bg_color, 0.3);
+      }
     }
 
     > label.day-number.other-month {