diff --git a/TaskTracker.Api/wwwroot/js/app.js b/TaskTracker.Api/wwwroot/js/app.js
index 0b7c419..a2bebe4 100644
--- a/TaskTracker.Api/wwwroot/js/app.js
+++ b/TaskTracker.Api/wwwroot/js/app.js
@@ -88,8 +88,11 @@
             if (Number.isNaN(dueAt)) return;
 
             var deltaMilliseconds = dueAt - now;
+            var deltaSeconds = Math.floor(deltaMilliseconds / 1000);
+            var overdue = deltaSeconds < 0;
             var totalSeconds = Math.floor(Math.abs(deltaMilliseconds) / 1000);
-            countdown.textContent = formatCountdown(totalSeconds, deltaMilliseconds > 0);
+            countdown.textContent = formatCountdown(totalSeconds, !overdue);
+            countdown.classList.toggle('task-countdown--overdue', overdue);
         });
     }