diff --git a/src/theme/style.css b/src/theme/style.css
index c12b400a..8008581b 100644
--- a/src/theme/style.css
+++ b/src/theme/style.css
@@ -321,6 +321,12 @@ monthcell.out-of-month:not(.today) {
     background-color: alpha(@sidebar_bg_color, 0.5);
 }
 
+monthcell:selected.out-of-month:not(.today) {
+    background-color: mix(alpha(@sidebar_bg_color, 0.5),
+                          alpha(@accent_bg_color, 0.1),
+                          0.5);
+}
+
 monthcell:not(.workday) {
     background-color: alpha(@theme_bg_color, 0.33);
 }
@@ -339,6 +345,14 @@ monthcell.out-of-month:hover {
     transition: background-color 200ms;
 }
 
+monthcell:selected:hover,
+monthcell:selected.out-of-month:hover {
+    background-color: mix(alpha(@theme_bg_color, 0.5),
+                          alpha(@accent_bg_color, 0.1),
+                          0.5);
+    transition: background-color 200ms;
+}
+
 monthcell button {
     font-weight: normal;
     padding: 0 4px;