fix(frontend): event description flotting out of page on long texts

Author: mercihabam

modules/calendar/site.css

@@ -4,3 +4,7 @@
 .calendar_week td { width: 14%; height: 600px; text-align: left; padding: 10px; border-bottom: solid 1px #eee; vertical-align: top; border-right: solid 1px #eee; }
 .event_details { cursor: pointer; z-index: 100; display: none; position: absolute; width: 300px; border: solid 1px #ddd; background-color: #fff; padding: 10px; }
 .event_details td { padding: 5px; border: none;  height: auto; }
+.event_detail {
+    max-height: 35vh;
+    overflow: auto;
+}