diff --git a/Sprint-3/alarmclock/alarmclock.js b/Sprint-3/alarmclock/alarmclock.js
index 6ca81cd3b..c98941666 100644
--- a/Sprint-3/alarmclock/alarmclock.js
+++ b/Sprint-3/alarmclock/alarmclock.js
@@ -1,4 +1,60 @@
-function setAlarm() {}
+let runningTimer;                                                                           // Store the interval ID for countdown timer                        
+let timeLeft = 0;                                                                           // Remaining time in seconds
+let flashInterval;                                                                          // Store interval ID for flashing background effect
+
+const random = num => Math.floor(Math.random() * (num + 1));                                // Return random integer to generate RGB color values for flashing background
+
+const setAlarm = () => {
+  clearInterval(runningTimer);                                                              // Clear any previous running timer
+
+  const timeInput = document.getElementById("alarmSet");                                    // Get user input element 
+  const inputSeconds = parseInt(timeInput.value, 10);                                       // Convert string input to integer and assign as 'inputSeconds'
+
+  if (!Number.isInteger(inputSeconds) || inputSeconds <= 0) {                               // Validate input: positive whole numbers only
+    alert("Please enter an integer greater than 0");
+    return;
+  }
+
+  timeLeft = inputSeconds;                                                                  // Store valid input in timeLeft variable
+  timeInput.value = "";                                                                     // Clear input field after valid value is entered
+  updateDisplay();                                                                          // Show initial countdown immediately
+
+  runningTimer = setInterval(() => {                                                        // Start runningTimer by creating an interval that runs every 1 second
+    timeLeft--;
+    updateDisplay();                                                                        // Decrease time left by 1 second and update the display
+
+    if (timeLeft <= 0) {                                                                    // Stop timer and play alarm sound once time is up
+      clearInterval(runningTimer);
+      playAlarm();
+    }
+  }, 1000);                                                                                 // Update time remaining display each second
+};
+
+const updateDisplay = () => {                                                               // Format and update runningTimer display
+  const mins = String(Math.floor(timeLeft / 60)).padStart(2, "0");                          // Format minutes and seconds with leading 0
+  const secs = String(timeLeft % 60).padStart(2, "0");
+  document.getElementById("timeRemaining").textContent = `Time Remaining: ${mins}:${secs}`; // Update display with formatted MM:SS time
+};
+
+const flashing = () => {                                                                    // Adding flashing effect to run when the alarm sounds
+  const [startFlash, pauseFlash] = [window.playAlarm, window.pauseAlarm];                   // Store the playAlarm and pauseAlarm functions to use as flashing trigger/ stop
+
+  window.playAlarm = () => {
+    startFlash();                                                                           // Run the original alarm response
+    flashInterval = setInterval(() => {                                                     // Start a new interval that changes the background colour 
+      document.body.style.backgroundColor =
+        `rgb(${random(255)}, ${random(255)}, ${random(255)})`;
+    }, 300);                                                                                //  Change background every 300ms to create flashing effect
+  };
+
+  window.pauseAlarm = () => {
+    pauseFlash();                                                                           // Apply the original pause sound logic to stop flashing 
+    clearInterval(flashInterval);                                                           // Stop flashing interval by pressing 'Stop Alarm' button
+    document.body.style.backgroundColor = "";                                               // Reset the background colour
+  };
+};
+
+window.addEventListener("DOMContentLoaded", flashing);
 
 // DO NOT EDIT BELOW HERE
 
diff --git a/Sprint-3/alarmclock/index.html b/Sprint-3/alarmclock/index.html
index 48e2e80d9..5de159cd6 100644
--- a/Sprint-3/alarmclock/index.html
+++ b/Sprint-3/alarmclock/index.html
@@ -4,7 +4,7 @@
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <link rel="stylesheet" href="style.css" />
-    <title>Title here</title>
+    <title>Alarm Clock app</title>
   </head>
   <body>
     <div class="centre">