diff --git a/frontend/src/index.css b/frontend/src/index.css
index a15d758..114da59 100644
--- a/frontend/src/index.css
+++ b/frontend/src/index.css
@@ -170,19 +170,19 @@
    the tint must target the frame itself, not the td. */
 .fc .fc-day-sat .fc-daygrid-day-frame,
 .fc .fc-day-sun .fc-daygrid-day-frame {
-  background-color: color-mix(in srgb, white 5%, transparent) !important;
+  background-color: rgba(255, 255, 255, 0.05) !important;
 }
 
 /* Weekend tint: header cells */
 .fc .fc-col-header-cell.fc-day-sat,
 .fc .fc-col-header-cell.fc-day-sun {
-  background-color: color-mix(in srgb, white 5%, hsl(0 0% 8% / 0.65)) !important;
+  background-color: rgba(255, 255, 255, 0.05) !important;
 }
 
 /* Weekend tint: timegrid column cells (week/day view) */
 .fc .fc-timegrid-col.fc-day-sat,
 .fc .fc-timegrid-col.fc-day-sun {
-  background-color: color-mix(in srgb, white 5%, transparent) !important;
+  background-color: rgba(255, 255, 255, 0.05) !important;
 }