Update calendar with multi-select

frontend/src/pages/calendar.css

@@ -114,6 +114,11 @@
   font-size: 12px;
 }
 
+.calendar-day--selected {
+  background-color: #e3f2fd;
+  border-color: #0066cc;
+}
+
 .calendar-day__events {
   display: flex;
   flex-wrap: wrap;
@@ -128,6 +133,71 @@
   flex-shrink: 0;
 }
 
+.calendar-week {
+  position: relative;
+}
+
+.calendar-week__day-cell {
+  display: flex;
+  flex-direction: column;
+  position: relative;
+}
+
+.calendar-week__days-grid {
+  display: contents;
+}
+
+.calendar-week__day-bars {
+  display: flex;
+  flex-direction: column;
+  gap: 2px;
+  padding: 0 2px;
+}
+
+.calendar-bar {
+  display: flex;
+  align-items: center;
+  padding: 4px 8px;
+  border-radius: 3px;
+  font-size: 12px;
+  color: #fff;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
+}
+
+.calendar-event {
+  display: flex;
+  align-items: center;
+  gap: 4px;
+  width: 100%;
+  background: none !important;
+}
+
+.calendar-event__label {
+  font-size: 12px;
+  font-weight: 500;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  color: inherit;
+}
+
+.calendar-event__badge {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  min-width: 18px;
+  height: 18px;
+  padding: 0 3px;
+  background-color: rgba(255, 255, 255, 0.3);
+  border-radius: 2px;
+  font-size: 10px;
+  font-weight: bold;
+  flex-shrink: 0;
+}
+
 .calendar__legend {
   padding: 16px;
   background-color: #f9f9f9;
@@ -144,7 +214,7 @@
 
 .calendar__legend-items {
   display: flex;
-  gap: 16px;
+  gap: 24px;
   flex-wrap: wrap;
 }
 
@@ -156,9 +226,51 @@
   color: #666;
 }
 
-.calendar__legend-item .calendar-event {
-  width: 12px !important;
-  height: 12px !important;
-  min-width: 12px;
+.calendar__legend-swatch {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 16px;
+  height: 16px;
+  border-radius: 2px;
   flex-shrink: 0;
+  font-size: 11px;
+  font-weight: bold;
+  color: #fff;
+}
+
+.calendar__legend-swatch--dubbeldag {
+  background-color: rgba(0, 0, 0, 0.2);
+  border: 1px solid #999;
+  color: #333;
+}
+
+.calendar__grid--with-week-numbers {
+  grid-template-columns: 50px repeat(7, 1fr);
+}
+
+.calendar__week-number-header {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: 12px 8px;
+  font-weight: 600;
+  font-size: 12px;
+  color: #999;
+}
+
+.calendar__week-number {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: 8px;
+  font-weight: 600;
+  font-size: 11px;
+  color: #999;
+  border-right: 1px solid #e0e0e0;
+  background-color: #fafafa;
+}
+
+.calendar__week-number-text {
+  display: block;
 }