<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Digital Time Timer</title>
  <style>
    #timer {
      font-size: 2em;
      text-align: center;
      margin-top: 50px;
    }
  </style>
</head>
<body>
  <div id="timer">25:00</div>
  <button onclick="startTimer()">Start</button>
  <button onclick="resetTimer()">Reset</button>
  <script>
    let timeLeft = 25 * 60;  // Set initial time (25 minutes)
    let timerInterval;
    function startTimer() {
      timerInterval = setInterval(() => {
        if (timeLeft > 0) {
          timeLeft--;
          document.getElementById("timer").textContent = formatTime(timeLeft);
        } else {
          clearInterval(timerInterval);
          alert("Time's up!");
        }
      }, 1000);
    }
    function resetTimer() {
      clearInterval(timerInterval);
      timeLeft = 25 * 60;
      document.getElementById("timer").textContent = "25:00";
    }
    function formatTime(seconds) {
      let minutes = Math.floor(seconds / 60);
      let secs = seconds % 60;
      return `${minutes}:${secs < 10 ? '0' : ''}${secs}`;
    }
  </script>
</body>
</html>