function formatTime(seconds) {
    return `00:${seconds.toString().padStart(2, '0')}`;
}

function startTimer() {
    if (isRunning) return;
    
    isRunning = true;
    startButton.textContent = 'Running...';
    startButton.style.background = '#27ae60';
    
    timerId = setInterval(() => {
        timeLeft--;
        timerDisplay.textContent = formatTime(timeLeft);
        
        if (timeLeft <= 0) {
            clearInterval(timerId);
            if (soundEnabled) {
                audio.play();
            }
            resetTimer();
        }
    }, 1000);
}

function resetTimer() {
    clearInterval(timerId);
    timeLeft = 10;
    isRunning = false;
    timerDisplay.textContent = formatTime(timeLeft);
    startButton.textContent = 'Start';
    startButton.style.background = '#2ecc71';
}

function toggleSound() {
    soundEnabled = !soundEnabled;
    soundButton.innerHTML = soundEnabled ? '🔊 Sound On' : '🔇 Sound Off';
    soundButton.style.background = soundEnabled ? '#3498db' : '#95a5a6';
}

// Handle keyboard shortcuts
document.addEventListener('keydown', (e) => {
    if (e.code === 'Space') {
        e.preventDefault();
        if (isRunning) {
            resetTimer();
        } else {
            startTimer();
        }
    }
});

// Handle visibility change
document.addEventListener('visibilitychange', () => {
    if (document.hidden && isRunning) {
        resetTimer();
    }
});

// Mobile touch feedback
document.querySelectorAll('button').forEach(button => {
    button.addEventListener('touchstart', () => {
        button.style.transform = 'scale(0.95)';
    });
    button.addEventListener('touchend', () => {
        button.style.transform = 'scale(1)';
    });
});