._.

WEB/app/src/app/app.css

@@ -202,4 +202,8 @@
     z-index: 1001;
     position: absolute;
     border: 1px solid black;
+}
+
+.calendar-weekend {
+    color: red !important;
 }

WEB/app/src/app/components/сalendar.js

@@ -94,10 +94,12 @@ const Calendar = () => {
                     const eventCount = dayEvents.length;
                     const backgroundColor = eventCount > 0 ? getEventColor(eventCount) : "transparent";
 
+                    const weekendClass = [5, 6].includes(index % 7) ? "calendar-weekend" : "";
+
                     return (
                         <div
                             key={index}
-                            className={`calendar-day ${
+                            className={`calendar-day ${weekendClass} ${
                                 today.getFullYear() === year &&
                                 today.getMonth() === month &&
                                 today.getDate() === day