How to Use Timer:
- Enter hours (HH), minutes (MM), and seconds (SS) in the input fields (e.g., 01, 30, 00 for 1 hour 30 minutes).
- Click "Start" to begin the countdown (button changes to "Pause").
- Click "Pause" to pause; click "Start" again to resume.
- Click "Stop" to halt the timer completely.
- Click "Reset" to clear the time and inputs back to 00:00:00.
- When the timer reaches zero, an alert says "Time's up!".