string alterations

Move CountDownTimer logic from a Dialog into a ForegroundService so
the timer survives when the user tabs away or the activity is
destroyed. The activity becomes a thin UI projection bound to the
service via TimerStateListener callbacks.

- Create CountdownService with notification, state persistence,
  and ToneGenerator/Vibrator ownership
- Persist timer state to SharedPreferences for process death recovery
- Add notification with progress bar and Stop/Restart actions
- Embed countdown UI in activity_main.xml alongside picker UI
- Delete CountdownDialog and dialog_countdown.xml
- Update AndroidManifest with foreground service permissions

.devcontainer/Dockerfile

@@ -1,31 +1,33 @@
-FROM mcr.microsoft.com/devcontainers/java:dev-17-jdk-trixie
+FROM ghcr.io/alvr/alpine-android:android-34-jdk21
 
 # Install Android SDK command-line tools
 # ARG ANDROID_CMDLINE_TOOLS_VERSION=11076708
-ARG ANDROID_BUILD_TOOLS_VERSION=34.0.0
+# ARG ANDROID_BUILD_TOOLS_VERSION=34.0.0
-ARG ANDROID_SDK_URL="https://dl.google.com/android/repository/commandlinetools-linux-11076708_latest.zip"
+# ARG ANDROID_SDK_URL="https://dl.google.com/android/repository/commandlinetools-linux-11076708_latest.zip"
 
-RUN mkdir -p /usr/local/android-sdk/cmdline-tools && \
+# RUN apk update && apk add curl zip git openjdk21-jdk cmake gcc
-    cd /tmp && \
-    curl -fsSL "$ANDROID_SDK_URL" -o cmdline-tools.zip && \
-    unzip -q cmdline-tools.zip -d /usr/local/android-sdk/cmdline-tools && \
-    mv /usr/local/android-sdk/cmdline-tools/cmdline-tools /usr/local/android-sdk/cmdline-tools/latest && \
-    rm cmdline-tools.zip
 
-# Set Android SDK paths and environment
+#  RUN mkdir -p /usr/local/android-sdk/cmdline-tools && \
-ENV ANDROID_HOME=/usr/local/android-sdk
+#     cd /tmp && \
-ENV ANDROID_COMMAND_LINE_TOOL=/usr/local/android-sdk/cmdline-tools/latest/bin
+#     curl -fsSL "$ANDROID_SDK_URL" -o cmdline-tools.zip && \
-ENV PATH=${ANDROID_HOME}/cmdline-tools/latest/bin:${ANDROID_HOME}/platform-tools:${PATH}
+#     unzip -q cmdline-tools.zip -d /usr/local/android-sdk/cmdline-tools && \
+#     mv /usr/local/android-sdk/cmdline-tools/cmdline-tools /usr/local/android-sdk/cmdline-tools/latest && \
+#     rm cmdline-tools.zip
 
-# Accept licenses and install required SDK packages
+# # Set Android SDK paths and environment
-RUN mkdir -p $ANDROID_HOME/.android && \
+# ENV ANDROID_HOME=/usr/local/android-sdk
-    touch $ANDROID_HOME/.android/repositories.cfg && \
+# ENV ANDROID_COMMAND_LINE_TOOL=/usr/local/android-sdk/cmdline-tools/latest/bin
-    yes | ${ANDROID_COMMAND_LINE_TOOL}/sdkmanager --licenses 2>/dev/null || true && \
+# ENV PATH=${ANDROID_HOME}/cmdline-tools/latest/bin:${ANDROID_HOME}/platform-tools:${PATH}
-    ${ANDROID_COMMAND_LINE_TOOL}/sdkmanager \
-    "platforms;android-34" \
-    "build-tools;33.0.1" \
-    "platform-tools" \
-    2>&1 | tee /dev/null
 
-# Grant execute permission to gradlew
+# # Accept licenses and install required SDK packages
-RUN chmod +x /workspaces/*/gradlew 2>/dev/null || true
+# RUN mkdir -p $ANDROID_HOME/.android && \
+#     touch $ANDROID_HOME/.android/repositories.cfg && \
+#     yes | ${ANDROID_COMMAND_LINE_TOOL}/sdkmanager --licenses 2>/dev/null || true && \
+#     ${ANDROID_COMMAND_LINE_TOOL}/sdkmanager \
+#     "platforms;android-34" \
+#     "build-tools;33.0.1" \
+#     "platform-tools" \
+#     2>&1 | tee /dev/null
+
+# # Grant execute permission to gradlew
+# RUN chmod +x /workspaces/*/gradlew 2>/dev/null || true

.devcontainer/devcontainer.json

@@ -7,7 +7,10 @@
                 "redhat.vscode-xml",
                 "redhat.vscode-yaml",
                 "felipecaslazana.vscode-android-logcat",
-                "ms-azuretools.vscode-docker"
+                "ms-azuretools.vscode-docker",
+                "fwcd.kotlin",
+                "vscjava.vscode-java-pack",
+                "Anthropic.claude-code"
             ]
         }
     },

CLAUDE.md

@@ -17,16 +17,19 @@
 - **Android Patterns**: Use `findViewById` for view binding in this project to maintain consistency with existing simple architecture.
 
 ## Architecture
-- **Pattern**: Simple Activity-Dialog architecture.
+- **Pattern**: Activity-Service architecture with `ForegroundService`.
-- **State**: The countdown state is managed locally within `CountdownDialog` using `android.os.CountDownTimer`.
+- **State**: The countdown state is managed in `CountdownService` using `android.os.CountDownTimer`, persisted to `SharedPreferences` for process death recovery.
+- **UI**: `MainActivity` binds to the service and acts as a thin UI projection, receiving state updates via `TimerStateListener` callback.
 - **Dependency Management**: Gradle with Groovy DSL.
 - **Key Constraints**:
-  - The `CountdownDialog` is explicitly set to `setCancelable(false)` and `setCanceledOnTouchOutside(false)` to ensure the timer completes.
+  - The notification is set to `setOngoing(true)` — cannot be swiped away.
+  - Timer state survives process death via `SharedPreferences` persistence.
 
 ## Critical Files Reference
-- `app/src/main/java/com/example/countdowntimer/MainActivity.kt`: Entry point and trigger for the timer.
+- `app/src/main/java/com/example/countdowntimer/MainActivity.kt`: Entry point, binds to service, implements `TimerStateListener`.
-- `app/src/main/java/com/example/countdowntimer/CountdownDialog.kt`: Implementation of the countdown logic and `ToneGenerator` trigger.
+- `app/src/main/java/com/example/countdowntimer/CountdownService.kt`: ForegroundService owning timer logic, `ToneGenerator`, `Vibrator`, notification, and state persistence.
+- `app/src/main/java/com/example/countdowntimer/TimerStateListener.kt`: Callback interface for service-to-activity state updates.
 - `app/src/main/java/com/example/countdowntimer/CountdownCanvasView.kt`: Custom view for the circular progress ring and countdown text.
-- `app/src/main/res/layout/activity_main.xml`: Main screen layout.
+- `app/src/main/res/layout/activity_main.xml`: Main screen layout (contains both picker and countdown UI).
-- `app/src/main/res/layout/dialog_countdown.xml`: Timer dialog layout.
+- `app/src/main/AndroidManifest.xml`: Declares service and foreground service permissions.
-- `app/build.gradle`: Build configuration, SDK versions (minSdk 24, targetSdk 34), and dependencies.
+- `app/build.gradle`: Build configuration, SDK versions (minSdk 34, targetSdk 34), and dependencies.

app/src/main/AndroidManifest.xml

@@ -1,6 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
     <uses-permission android:name="android.permission.VIBRATE" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE_DATA_SYNC" />
     <application
         android:allowBackup="true"
         android:icon="@drawable/ic_timer"
@@ -16,5 +18,10 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+        <service
+            android:name=".CountdownService"
+            android:enabled="true"
+            android:exported="false"
+            android:foregroundServiceType="dataSync" />
     </application>
 </manifest>

app/src/main/java/com/example/countdowntimer/CountdownCanvasView.kt

@@ -47,6 +47,13 @@ class CountdownCanvasView @JvmOverloads constructor(
         invalidate()
     }
 
+    fun setColor(color: Int) {
+        if (ringPaint.color != color) {
+            ringPaint.color = color
+            invalidate()
+        }
+    }
+
     override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {
         super.onSizeChanged(w, h, oldw, oldh)
         val inset = ringPaint.strokeWidth / 2f + 12f

app/src/main/java/com/example/countdowntimer/CountdownDialog.kt

@@ -1,113 +0,0 @@
-package com.example.countdowntimer
-
-import android.app.Dialog
-import android.content.Context
-import android.content.SharedPreferences
-import android.media.AudioManager
-import android.media.ToneGenerator
-import android.os.Bundle
-import android.os.CountDownTimer
-import android.os.Vibrator
-import android.view.View
-import android.view.WindowManager
-import android.widget.Button
-
-class CountdownDialog(
-    private val context: Context,
-    private val durationMillis: Long,
-    private val prefs: SharedPreferences
-) : Dialog(context) {
-    private lateinit var cvCountdown: CountdownCanvasView
-    private lateinit var btnStop: View
-    private lateinit var btnRestart: View
-    private lateinit var btnDismiss: Button
-    private var timer: CountDownTimer? = null
-    private var toneGenerator: ToneGenerator? = null
-    private var vibrator: Vibrator? = null
-
-    override fun onCreate(savedInstanceState: Bundle?) {
-        super.onCreate(savedInstanceState)
-        setContentView(R.layout.dialog_countdown)
-
-        setCanceledOnTouchOutside(false)
-        setCancelable(false)
-
-        window?.let { win ->
-            win.setBackgroundDrawableResource(android.R.color.transparent)
-            val lp = win.attributes
-            lp.width = WindowManager.LayoutParams.MATCH_PARENT
-            lp.height = WindowManager.LayoutParams.MATCH_PARENT
-            win.attributes = lp
-        }
-
-        cvCountdown = findViewById(R.id.cvCountdown)
-        btnStop = findViewById(R.id.btnStop)
-        btnRestart = findViewById(R.id.btnRestart)
-        btnDismiss = findViewById(R.id.btnDismiss)
-        toneGenerator = ToneGenerator(AudioManager.STREAM_ALARM, 100)
-        vibrator = context.getSystemService(Context.VIBRATOR_SERVICE) as Vibrator
-
-        btnStop.setOnClickListener { cancelTimer() }
-        btnRestart.setOnClickListener { restartTimer() }
-        btnDismiss.setOnClickListener { dismiss() }
-
-        startTimer()
-    }
-
-    private fun startTimer() {
-        cvCountdown.setProgress(1f)
-        timer = object : CountDownTimer(durationMillis, 1000) {
-            override fun onTick(millisUntilFinished: Long) {
-                val progress = millisUntilFinished.toFloat() / durationMillis
-                cvCountdown.setProgress(progress)
-
-                val secondsLeft = (millisUntilFinished / 1000).toInt() + 1
-                cvCountdown.setText(secondsLeft.toString())
-
-                if (secondsLeft >= 1 && secondsLeft <= 3) {
-                    playTone(ToneGenerator.TONE_PROP_BEEP)
-                    if (prefs.getBoolean("vibration", true)) {
-                        vibrator?.vibrate(50)
-                    }
-                }
-            }
-
-            override fun onFinish() {
-                cvCountdown.setText(context.getString(R.string.timer_zero))
-                cvCountdown.setProgress(0f)
-                playTone(ToneGenerator.TONE_SUP_CONFIRM, 500)
-                if (prefs.getBoolean("vibration", true)) {
-                    vibrator?.vibrate(200)
-                }
-                btnStop.visibility = View.GONE
-                btnRestart.visibility = View.GONE
-                btnDismiss.visibility = View.VISIBLE
-            }
-        }.start()
-    }
-
-    private fun cancelTimer() {
-        timer?.cancel()
-        dismiss()
-    }
-
-    private fun restartTimer() {
-        timer?.cancel()
-        startTimer()
-    }
-
-    override fun dismiss() {
-        timer?.cancel()
-        toneGenerator?.release()
-        toneGenerator = null
-        super.dismiss()
-    }
-
-    private fun playTone(tone: Int, durationMillis: Int? = null) {
-        if (durationMillis == null) {
-            toneGenerator?.startTone(tone)
-        } else {
-            toneGenerator?.startTone(tone, durationMillis)
-        }
-    }
-}

app/src/main/java/com/example/countdowntimer/CountdownService.kt

@@ -0,0 +1,263 @@
+package com.example.countdowntimer
+
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.PendingIntent
+import android.app.Service
+import android.content.Context
+import android.content.Intent
+import android.content.SharedPreferences
+import android.media.AudioManager
+import android.media.ToneGenerator
+import android.os.Binder
+import android.os.CountDownTimer
+import android.os.IBinder
+import android.os.VibrationEffect
+import android.os.Vibrator
+import android.os.VibratorManager
+import androidx.core.app.NotificationCompat
+import androidx.core.graphics.ColorUtils
+
+class CountdownService : Service() {
+
+    companion object {
+        const val ACTION_START = "com.example.countdowntimer.START"
+        const val ACTION_STOP = "com.example.countdowntimer.STOP"
+        const val ACTION_RESTART = "com.example.countdowntimer.RESTART"
+        const val EXTRA_DURATION = "extra_duration"
+
+        private const val NOTIFICATION_ID = 1
+        private const val CHANNEL_ID = "countdown_channel"
+        private const val CHANNEL_NAME = "Countdown Timer"
+        private const val PREFS_NAME = "timer_prefs"
+        private const val KEY_REMAINING_MILLIS = "remaining_millis"
+        private const val KEY_TOTAL_DURATION = "total_duration"
+        private const val KEY_TIMER_RUNNING = "timer_running"
+    }
+
+    private var countDownTimer: CountDownTimer? = null
+    private var toneGenerator: ToneGenerator? = null
+    private var vibrator: Vibrator? = null
+    private var prefs: SharedPreferences? = null
+    private var stateListener: TimerStateListener? = null
+    private var durationMillis: Long = 0
+    private var notificationManager: NotificationManager? = null
+    private var isTimerRunning: Boolean = false
+
+    private val binder = LocalBinder()
+
+    inner class LocalBinder : Binder() {
+        fun getService(): CountdownService = this@CountdownService
+    }
+
+    fun setStateListener(listener: TimerStateListener?) {
+        stateListener = listener
+    }
+
+    fun isRunning(): Boolean = isTimerRunning
+
+    // ---- Service lifecycle ----
+
+    override fun onCreate() {
+        super.onCreate()
+
+        prefs = getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE)
+        notificationManager = getSystemService(NOTIFICATION_SERVICE) as NotificationManager
+        toneGenerator = ToneGenerator(AudioManager.STREAM_ALARM, 100)
+
+        val vibratorManager = getSystemService(Context.VIBRATOR_MANAGER_SERVICE) as VibratorManager
+        vibrator = vibratorManager.defaultVibrator
+
+        createNotificationChannel()
+
+        // Restore timer state if it was running before process death
+        if (prefs?.getBoolean(KEY_TIMER_RUNNING, false) == true) {
+            val remaining = prefs?.getLong(KEY_REMAINING_MILLIS, 0) ?: 0
+            durationMillis = prefs?.getLong(KEY_TOTAL_DURATION, 0) ?: 0
+            if (remaining > 0 && durationMillis > 0) {
+                resumeTimer(remaining)
+            }
+        }
+    }
+
+    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
+        val action = intent?.action
+        when (action) {
+            ACTION_START -> {
+                val duration = intent.getLongExtra(EXTRA_DURATION, 600000L)
+                startTimer(duration)
+            }
+            ACTION_STOP -> stopTimer()
+            ACTION_RESTART -> restartTimer()
+        }
+        return START_NOT_STICKY
+    }
+
+    override fun onBind(intent: Intent?): IBinder = binder
+
+    override fun onDestroy() {
+        countDownTimer?.cancel()
+        countDownTimer = null
+        toneGenerator?.release()
+        toneGenerator = null
+        notificationManager?.cancel(NOTIFICATION_ID)
+        super.onDestroy()
+    }
+
+    // ---- Timer logic ----
+
+    private fun startTimer(duration: Long) {
+        durationMillis = duration
+        countDownTimer?.cancel()
+        countDownTimer = createCountDownTimer(duration).start()
+        isTimerRunning = true
+
+        persistState(duration, duration)
+        startForeground(NOTIFICATION_ID, buildNotification(duration, duration))
+    }
+
+    private fun resumeTimer(remaining: Long) {
+        isTimerRunning = true
+        countDownTimer = createCountDownTimer(remaining).start()
+        startForeground(NOTIFICATION_ID, buildNotification(remaining, durationMillis))
+    }
+
+    fun stopTimer() {
+        countDownTimer?.cancel()
+        countDownTimer = null
+        isTimerRunning = false
+
+        prefs?.edit()?.apply {
+            putBoolean(KEY_TIMER_RUNNING, false)
+            remove(KEY_REMAINING_MILLIS)
+            remove(KEY_TOTAL_DURATION)
+        }?.apply()
+
+        notificationManager?.cancel(NOTIFICATION_ID)
+        stopForeground(STOP_FOREGROUND_REMOVE)
+        stopSelf()
+        stateListener?.onTimerStopped()
+    }
+
+    fun restartTimer() {
+        countDownTimer?.cancel()
+        startTimer(durationMillis)
+    }
+
+    private fun persistState(remaining: Long, total: Long) {
+        prefs?.edit()?.apply {
+            putLong(KEY_REMAINING_MILLIS, remaining)
+            putLong(KEY_TOTAL_DURATION, total)
+            putBoolean(KEY_TIMER_RUNNING, true)
+        }?.apply()
+    }
+
+    private fun createCountDownTimer(remaining: Long): CountDownTimer {
+        return object : CountDownTimer(remaining, 1000) {
+            override fun onTick(millisUntilFinished: Long) {
+                val progress = millisUntilFinished.toFloat() / durationMillis
+
+                // Persist remaining time
+                persistState(millisUntilFinished, durationMillis)
+
+                // Color interpolation: green → yellow at 50% → red at end
+                val green = android.graphics.Color.parseColor("#2E7D32")
+                val yellow = android.graphics.Color.parseColor("#FFC107")
+                val red = android.graphics.Color.parseColor("#F44336")
+                val ringColor = when {
+                    progress >= 0.5f -> {
+                        val t = (progress - 0.5f) * 2f
+                        ColorUtils.blendARGB(green, yellow, t)
+                    }
+                    else -> {
+                        val t = progress * 2f
+                        ColorUtils.blendARGB(yellow, red, t)
+                    }
+                }
+
+                val secondsLeft = (millisUntilFinished / 1000).toInt() + 1
+
+                // Warning beeps and vibration in last 3 seconds
+                if (secondsLeft >= 1 && secondsLeft <= 3) {
+                    toneGenerator?.startTone(ToneGenerator.TONE_PROP_BEEP)
+                    vibrator?.vibrate(VibrationEffect.createOneShot(50, VibrationEffect.DEFAULT_AMPLITUDE))
+                }
+
+                // Update notification
+                updateNotification(millisUntilFinished, durationMillis)
+
+                // Push state to activity
+                stateListener?.onTimerTick(millisUntilFinished, durationMillis, secondsLeft, ringColor)
+            }
+
+            override fun onFinish() {
+                isTimerRunning = false
+                prefs?.edit()?.putBoolean(KEY_TIMER_RUNNING, false)?.apply()
+
+                toneGenerator?.startTone(ToneGenerator.TONE_SUP_CONFIRM, 500)
+                vibrator?.vibrate(VibrationEffect.createOneShot(200, VibrationEffect.DEFAULT_AMPLITUDE))
+
+                updateNotification(0, durationMillis)
+                stateListener?.onTimerFinished()
+            }
+        }
+    }
+
+    // ---- Notification ----
+
+    private fun createNotificationChannel() {
+        val channel = NotificationChannel(
+            CHANNEL_ID, CHANNEL_NAME, NotificationManager.IMPORTANCE_LOW
+        ).apply {
+            description = "Countdown timer progress"
+            lockscreenVisibility = android.app.Notification.VISIBILITY_PUBLIC
+        }
+        notificationManager?.createNotificationChannel(channel)
+    }
+
+    private fun buildNotification(remainingMillis: Long, totalMillis: Long): android.app.Notification {
+        val secondsRemaining = (remainingMillis / 1000).toInt()
+        val minutes = secondsRemaining / 60
+        val seconds = secondsRemaining % 60
+        val timeText = String.format("%02d:%02d", minutes, seconds)
+        val progressPercent = if (totalMillis > 0) {
+            ((1 - remainingMillis.toFloat() / totalMillis) * 100).toInt()
+        } else {
+            0
+        }
+
+        val stopPendingIntent = PendingIntent.getService(
+            this, 0,
+            Intent(this, CountdownService::class.java).apply { action = ACTION_STOP },
+            PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT
+        )
+
+        val restartPendingIntent = PendingIntent.getService(
+            this, 1,
+            Intent(this, CountdownService::class.java).apply { action = ACTION_RESTART },
+            PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT
+        )
+
+        val activityPendingIntent = PendingIntent.getActivity(
+            this, 2,
+            Intent(this, MainActivity::class.java),
+            PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT
+        )
+
+        return NotificationCompat.Builder(this, CHANNEL_ID)
+            .setContentTitle("Bong Hit Timer")
+            .setContentText(timeText)
+            .setSmallIcon(R.drawable.ic_timer)
+            .setProgress(100, progressPercent, false)
+            .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)
+            .setOngoing(true)
+            .addAction(R.drawable.ic_stop_square, "Stop", stopPendingIntent)
+            .addAction(R.drawable.ic_refresh_square, "Restart", restartPendingIntent)
+            .setContentIntent(activityPendingIntent)
+            .build()
+    }
+
+    private fun updateNotification(remainingMillis: Long, totalMillis: Long) {
+        notificationManager?.notify(NOTIFICATION_ID, buildNotification(remainingMillis, totalMillis))
+    }
+}

app/src/main/java/com/example/countdowntimer/MainActivity.kt

@@ -1,40 +1,66 @@
 package com.example.countdowntimer
 
+import android.content.ComponentName
 import android.content.Context
+import android.content.Intent
+import android.content.ServiceConnection
 import android.content.SharedPreferences
 import android.os.Bundle
+import android.os.IBinder
+import android.os.VibrationEffect
+import android.os.Vibrator
+import android.os.VibratorManager
 import android.view.View
 import android.view.inputmethod.InputMethodManager
 import android.widget.Button
 import androidx.appcompat.app.AppCompatActivity
 import com.google.android.material.chip.ChipGroup
+import android.animation.ValueAnimator
+import android.view.animation.AnticipateOvershootInterpolator
 
-class MainActivity : AppCompatActivity() {
+class MainActivity : AppCompatActivity(), TimerStateListener {
 
     companion object {
         private const val PREFS_NAME = "timer_prefs"
         private const val KEY_SELECTED_DURATION = "selected_duration"
-        private const val DEFAULT_DURATION = 10000L
+        private const val DEFAULT_DURATION = 600000L
     }
 
     private lateinit var prefs: SharedPreferences
     private lateinit var btnDurationLabel: Button
     private lateinit var hsvDurationOptions: View
     private lateinit var chipGroup: ChipGroup
+    private lateinit var btnStart: View
+    private lateinit var vibrator: Vibrator
     private var selectedDuration: Long = DEFAULT_DURATION
+    private var lastSelectedChipId: Int = -1
+    private var pulseAnimator: ValueAnimator? = null
+
+    // Service binding
+    private var service: CountdownService? = null
+    private var serviceBound = false
+    private lateinit var serviceConnection: ServiceConnection
+
+    // Countdown UI views
+    private lateinit var cvCountdown: CountdownCanvasView
+    private lateinit var btnStop: View
+    private lateinit var btnRestart: View
+    private lateinit var btnDismiss: Button
+    private lateinit var countdownLayout: View
+    private lateinit var pickerLayout: View
 
     private fun durationToChipId(duration: Long): Int = when (duration) {
-        5000L -> R.id.chip5s
+        300000L -> R.id.chip5m
-        15000L -> R.id.chip15s
+        600000L -> R.id.chip10m
-        30000L -> R.id.chip30s
+        900000L -> R.id.chip15m
-        else -> R.id.chip10s
+        else -> R.id.chip10m
     }
 
     private fun chipIdToDuration(chipId: Int): Long = when (chipId) {
-        R.id.chip5s -> 5000L
+        R.id.chip5m -> 300000L
-        R.id.chip10s -> 10000L
+        R.id.chip10m -> 600000L
-        R.id.chip15s -> 15000L
+        R.id.chip15m -> 900000L
-        R.id.chip30s -> 30000L
+        R.id.chip30m -> 1800000L
         else -> DEFAULT_DURATION
     }
 
@@ -42,6 +68,98 @@ class MainActivity : AppCompatActivity() {
         btnDurationLabel.text = "${selectedDuration / 1000}s"
     }
 
+    private fun onChipClicked(chipId: Int) {
+        if (chipId == lastSelectedChipId) {
+            vibrator.vibrate(VibrationEffect.createOneShot(15, VibrationEffect.DEFAULT_AMPLITUDE))
+            val originalText = btnDurationLabel.text
+            btnDurationLabel.text = "${selectedDuration / 1000}s!"
+            btnDurationLabel.postDelayed({ btnDurationLabel.text = originalText }, 300)
+        }
+    }
+
+    private fun startPulseAnimation() {
+        pulseAnimator = ValueAnimator.ofFloat(1f, 0.78f, 1f).apply {
+            duration = 1500
+            repeatMode = ValueAnimator.REVERSE
+            repeatCount = ValueAnimator.INFINITE
+            interpolator = AnticipateOvershootInterpolator(1f)
+            addUpdateListener { animation ->
+                val fraction = animation.animatedValue as Float
+                btnStart.scaleX = fraction
+                btnStart.scaleY = fraction
+                btnStart.alpha = fraction
+            }
+        }
+        pulseAnimator?.start()
+    }
+
+    private fun stopPulseAnimation() {
+        pulseAnimator?.cancel()
+        pulseAnimator = null
+        btnStart.scaleX = 1f
+        btnStart.scaleY = 1f
+        btnStart.alpha = 1f
+    }
+
+    private fun showCountdownUI() {
+        pickerLayout.visibility = View.GONE
+        countdownLayout.visibility = View.VISIBLE
+        stopPulseAnimation()
+    }
+
+    private fun hideCountdownUI() {
+        countdownLayout.visibility = View.GONE
+        pickerLayout.visibility = View.VISIBLE
+        btnDismiss.visibility = View.GONE
+        btnStop.visibility = View.VISIBLE
+        btnRestart.visibility = View.VISIBLE
+        startPulseAnimation()
+    }
+
+    // ---- ServiceConnection ----
+
+    private fun initServiceConnection() {
+        serviceConnection = object : ServiceConnection {
+            override fun onServiceConnected(name: ComponentName?, binder: IBinder?) {
+                val localBinder = binder as CountdownService.LocalBinder
+                service = localBinder.getService()
+                serviceBound = true
+                service?.setStateListener(this@MainActivity)
+                if (service?.isRunning() == true) {
+                    showCountdownUI()
+                }
+            }
+
+            override fun onServiceDisconnected(name: ComponentName?) {
+                serviceBound = false
+                service = null
+            }
+        }
+    }
+
+    // ---- TimerStateListener callbacks ----
+
+    override fun onTimerTick(remainingMillis: Long, totalDuration: Long, secondsLeft: Int, ringColor: Int) {
+        val progress = remainingMillis.toFloat() / totalDuration
+        cvCountdown.setProgress(progress)
+        cvCountdown.setColor(ringColor)
+        cvCountdown.setText(secondsLeft.toString())
+    }
+
+    override fun onTimerFinished() {
+        cvCountdown.setText(getString(R.string.timer_zero))
+        cvCountdown.setProgress(0f)
+        btnStop.visibility = View.GONE
+        btnRestart.visibility = View.GONE
+        btnDismiss.visibility = View.VISIBLE
+    }
+
+    override fun onTimerStopped() {
+        hideCountdownUI()
+    }
+
+    // ---- Activity lifecycle ----
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
@@ -49,9 +167,21 @@ class MainActivity : AppCompatActivity() {
         prefs = getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE)
         selectedDuration = prefs.getLong(KEY_SELECTED_DURATION, DEFAULT_DURATION)
 
+        // Picker UI views
         btnDurationLabel = findViewById(R.id.btnDurationLabel)
         hsvDurationOptions = findViewById(R.id.hsvDurationOptions)
         chipGroup = findViewById(R.id.chipGroup)
+        btnStart = findViewById(R.id.btnStart)
+        val vibratorManager = getSystemService(Context.VIBRATOR_MANAGER_SERVICE) as VibratorManager
+        vibrator = vibratorManager.defaultVibrator
+
+        // Countdown UI views
+        cvCountdown = findViewById(R.id.cvCountdown)
+        btnStop = findViewById(R.id.btnStop)
+        btnRestart = findViewById(R.id.btnRestart)
+        btnDismiss = findViewById(R.id.btnDismiss)
+        countdownLayout = findViewById(R.id.countdownLayout)
+        pickerLayout = findViewById(R.id.pickerLayout)
 
         updateDurationLabel()
 
@@ -72,17 +202,70 @@ class MainActivity : AppCompatActivity() {
             }
         }
 
-        chipGroup.setOnCheckedChangeListener { _, checkedId ->
+        chipGroup.setOnCheckedStateChangeListener { _, checkedIds ->
+            val checkedId = if (checkedIds.size > 0) checkedIds[0].toInt() else -1
             if (checkedId != -1) {
-                selectedDuration = chipIdToDuration(checkedId)
+                if (checkedId != lastSelectedChipId) {
-                prefs.edit().putLong(KEY_SELECTED_DURATION, selectedDuration).apply()
+                    selectedDuration = chipIdToDuration(checkedId)
-                updateDurationLabel()
+                    prefs.edit().putLong(KEY_SELECTED_DURATION, selectedDuration).apply()
+                    updateDurationLabel()
+                    lastSelectedChipId = checkedId
+                }
                 hsvDurationOptions.visibility = View.GONE
             }
         }
 
-        findViewById<View>(R.id.btnStart).setOnClickListener {
+        findViewById<View>(R.id.chip5m).setOnClickListener { onChipClicked(R.id.chip5m) }
-            CountdownDialog(this, selectedDuration, prefs).show()
+        findViewById<View>(R.id.chip10m).setOnClickListener { onChipClicked(R.id.chip10m) }
+        findViewById<View>(R.id.chip15m).setOnClickListener { onChipClicked(R.id.chip15m) }
+        findViewById<View>(R.id.chip30m).setOnClickListener { onChipClicked(R.id.chip30m) }
+
+        // Start button: launch the service instead of showing a dialog
+        btnStart.setOnClickListener {
+            val intent = Intent(this, CountdownService::class.java).apply {
+                action = CountdownService.ACTION_START
+                putExtra(CountdownService.EXTRA_DURATION, selectedDuration)
+            }
+            startService(intent)
+            showCountdownUI()
+        }
+
+        // Countdown button handlers
+        btnStop.setOnClickListener { service?.stopTimer() }
+        btnRestart.setOnClickListener { service?.restartTimer() }
+        btnDismiss.setOnClickListener {
+            service?.stopTimer()
+            hideCountdownUI()
+        }
+
+        initServiceConnection()
+        startPulseAnimation()
+    }
+
+    override fun onStart() {
+        super.onStart()
+        Intent(this, CountdownService::class.java).also { intent ->
+            bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE)
         }
     }
-}
+
+    override fun onStop() {
+        super.onStop()
+        if (serviceBound) {
+            unbindService(serviceConnection)
+            serviceBound = false
+        }
+    }
+
+    override fun onResume() {
+        super.onResume()
+        if (!isFinishing && !isDestroyed && pickerLayout.visibility == View.VISIBLE) {
+            startPulseAnimation()
+        }
+    }
+
+    override fun onPause() {
+        super.onPause()
+        stopPulseAnimation()
+    }
+}

app/src/main/java/com/example/countdowntimer/TimerStateListener.kt

@@ -0,0 +1,7 @@
+package com.example.countdowntimer
+
+interface TimerStateListener {
+    fun onTimerTick(remainingMillis: Long, totalDuration: Long, secondsLeft: Int, ringColor: Int)
+    fun onTimerFinished()
+    fun onTimerStopped()
+}

app/src/main/res/color/chip_duration_bg.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
-    <item android:state_checked="true" android:color="#81C784" />
+    <item android:state_checked="true" android:color="#2E7D32" />
-    <item android:color="#E8E8E8" />
+    <item android:color="#233024" />
 </selector>

app/src/main/res/color/chip_duration_stroke.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:state_checked="true" android:color="#C8E6C9" />
+    <item android:color="#2E7D32" />
+</selector>

app/src/main/res/color/chip_duration_text.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:state_checked="true" android:color="#FFFFFF" />
+    <item android:color="#C8E6C9" />
+</selector>

app/src/main/res/layout/activity_main.xml

@@ -29,210 +29,304 @@
                     android:layout_height="wrap_content"
                     android:padding="24dp">
 
-                    <ImageView
+                    <!-- Picker UI -->
-                        android:id="@+id/timerIcon"
+                    <androidx.constraintlayout.widget.ConstraintLayout
-                        android:layout_width="80dp"
+                        android:id="@+id/pickerLayout"
-                        android:layout_height="80dp"
-                        android:src="@drawable/ic_timer"
-                        app:layout_constraintEnd_toEndOf="parent"
-                        app:layout_constraintStart_toStartOf="parent"
-                        app:layout_constraintTop_toTopOf="parent"
-                        app:tint="@color/color_icon_tint" />
-
-                    <TextView
-                        android:id="@+id/tvInstructionTitle"
                         android:layout_width="match_parent"
                         android:layout_height="wrap_content"
-                        android:layout_marginTop="16dp"
+                        android:visibility="visible"
-                        android:gravity="center"
+                        app:layout_constraintBottom_toBottomOf="parent"
-                        android:text="@string/instruction_title"
-                        android:textAppearance="@style/TextAppearance.Material3.HeadlineMedium"
-                        android:textStyle="bold"
                         app:layout_constraintEnd_toEndOf="parent"
                         app:layout_constraintStart_toStartOf="parent"
-                        app:layout_constraintTop_toBottomOf="@+id/timerIcon" />
+                        app:layout_constraintTop_toTopOf="parent">
 
-                    <LinearLayout
+                        <ImageView
-                        android:id="@+id/instructionsLayout"
+                            android:id="@+id/timerIcon"
-                        android:layout_width="wrap_content"
+                            android:layout_width="80dp"
-                        android:layout_height="wrap_content"
+                            android:layout_height="80dp"
-                        android:layout_marginTop="24dp"
+                            android:src="@drawable/ic_timer"
-                        android:orientation="vertical"
+                            app:layout_constraintEnd_toEndOf="parent"
-                        app:layout_constraintEnd_toEndOf="parent"
+                            app:layout_constraintStart_toStartOf="parent"
-                        app:layout_constraintStart_toStartOf="parent"
+                            app:layout_constraintTop_toTopOf="parent"
-                        app:layout_constraintTop_toBottomOf="@+id/tvInstructionTitle">
+                            app:tint="@color/color_icon_tint" />
 
-                        <LinearLayout
+                        <TextView
+                            android:id="@+id/tvInstructionTitle"
                             android:layout_width="match_parent"
                             android:layout_height="wrap_content"
-                            android:gravity="center_vertical"
+                            android:layout_marginTop="16dp"
-                            android:orientation="horizontal"
+                            android:gravity="center"
-                            android:padding="8dp">
+                            android:text="@string/instruction_title"
-
+                            android:textAppearance="@style/TextAppearance.Material3.HeadlineMedium"
-                            <ImageView
+                            android:textStyle="bold"
-                                android:layout_width="24dp"
+                            app:layout_constraintEnd_toEndOf="parent"
-                                android:layout_height="24dp"
+                            app:layout_constraintStart_toStartOf="parent"
-                                android:src="@drawable/outline_fire_check_24"
+                            app:layout_constraintTop_toBottomOf="@+id/timerIcon" />
-                                app:tint="@color/color_icon_tint" />
-
-                            <TextView
-                                android:layout_width="wrap_content"
-                                android:layout_height="wrap_content"
-                                android:layout_marginStart="12dp"
-                                android:text="@string/instruction_volume"
-                                android:textSize="16sp" />
-                        </LinearLayout>
 
                         <LinearLayout
-                            android:layout_width="match_parent"
+                            android:id="@+id/instructionsLayout"
-                            android:layout_height="wrap_content"
-                            android:gravity="center_vertical"
-                            android:orientation="horizontal"
-                            android:padding="8dp">
-
-                            <ImageView
-                                android:layout_width="24dp"
-                                android:layout_height="24dp"
-                                android:src="@drawable/outline_air_24"
-                                app:tint="@color/color_icon_tint" />
-
-                            <TextView
-                                android:layout_width="wrap_content"
-                                android:layout_height="wrap_content"
-                                android:layout_marginStart="12dp"
-                                android:text="@string/instruction_position"
-                                android:textSize="16sp" />
-                        </LinearLayout>
-
-                        <LinearLayout
-                            android:layout_width="match_parent"
-                            android:layout_height="wrap_content"
-                            android:gravity="center_vertical"
-                            android:orientation="horizontal"
-                            android:padding="8dp">
-
-                            <ImageView
-                                android:layout_width="24dp"
-                                android:layout_height="24dp"
-                                android:src="@drawable/ic_play_arrow"
-                                app:tint="@color/color_icon_tint" />
-
-                            <TextView
-                                android:layout_width="wrap_content"
-                                android:layout_height="wrap_content"
-                                android:layout_marginStart="12dp"
-                                android:text="@string/instruction_distractions"
-                                android:textSize="16sp" />
-                        </LinearLayout>
-                    </LinearLayout>
-
-                    <Button
-                        android:id="@+id/btnDurationLabel"
-                        android:layout_width="180dp"
-                        android:layout_height="80dp"
-                        android:layout_marginTop="32dp"
-                        android:background="@drawable/btn_duration_selector"
-                        android:drawableEnd="@drawable/ic_keyboard_arrow_down"
-                        android:drawablePadding="8dp"
-                        android:gravity="center"
-                        android:includeFontPadding="false"
-                        android:paddingStart="16dp"
-                        android:paddingEnd="16dp"
-                        android:text="@string/start_timer"
-                        android:textColor="#FFFFFF"
-                        android:textSize="18sp"
-                        android:textStyle="bold"
-                        app:layout_constraintEnd_toEndOf="parent"
-                        app:layout_constraintStart_toStartOf="parent"
-                        app:layout_constraintTop_toBottomOf="@+id/instructionsLayout" />
-
-                    <HorizontalScrollView
-                        android:id="@+id/hsvDurationOptions"
-                        android:layout_width="wrap_content"
-                        android:layout_height="wrap_content"
-                        android:layout_marginTop="8dp"
-                        android:scrollbars="none"
-                        android:visibility="gone"
-                        app:layout_constraintEnd_toEndOf="parent"
-                        app:layout_constraintStart_toStartOf="parent"
-                        app:layout_constraintTop_toBottomOf="@+id/btnDurationLabel">
-
-                        <com.google.android.material.chip.ChipGroup
-                            android:id="@+id/chipGroup"
                             android:layout_width="wrap_content"
                             android:layout_height="wrap_content"
-                            app:singleSelection="true">
+                            android:layout_marginTop="24dp"
+                            android:orientation="vertical"
+                            app:layout_constraintEnd_toEndOf="parent"
+                            app:layout_constraintStart_toStartOf="parent"
+                            app:layout_constraintTop_toBottomOf="@+id/tvInstructionTitle">
 
-                            <com.google.android.material.chip.Chip
+                            <LinearLayout
-                                android:id="@+id/chip5s"
+                                android:layout_width="match_parent"
-                                style="@style/Widget.Material3.Chip.Suggestion.Elevated"
+                                android:layout_height="wrap_content"
+                                android:gravity="center_vertical"
+                                android:orientation="horizontal"
+                                android:padding="8dp">
+
+                                <ImageView
+                                    android:layout_width="24dp"
+                                    android:layout_height="24dp"
+                                    android:src="@drawable/outline_fire_check_24"
+                                    app:tint="@color/color_icon_tint" />
+
+                                <TextView
+                                    android:layout_width="wrap_content"
+                                    android:layout_height="wrap_content"
+                                    android:layout_marginStart="12dp"
+                                    android:text="@string/instruction_volume"
+                                    android:textSize="16sp" />
+                            </LinearLayout>
+
+                            <LinearLayout
+                                android:layout_width="match_parent"
+                                android:layout_height="wrap_content"
+                                android:gravity="center_vertical"
+                                android:orientation="horizontal"
+                                android:padding="8dp">
+
+                                <ImageView
+                                    android:layout_width="24dp"
+                                    android:layout_height="24dp"
+                                    android:src="@drawable/outline_air_24"
+                                    app:tint="@color/color_icon_tint" />
+
+                                <TextView
+                                    android:layout_width="wrap_content"
+                                    android:layout_height="wrap_content"
+                                    android:layout_marginStart="12dp"
+                                    android:text="@string/instruction_position"
+                                    android:textSize="16sp" />
+                            </LinearLayout>
+
+                            <LinearLayout
+                                android:layout_width="match_parent"
+                                android:layout_height="wrap_content"
+                                android:gravity="center_vertical"
+                                android:orientation="horizontal"
+                                android:padding="8dp">
+
+                                <ImageView
+                                    android:layout_width="24dp"
+                                    android:layout_height="24dp"
+                                    android:src="@drawable/ic_play_arrow"
+                                    app:tint="@color/color_icon_tint" />
+
+                                <TextView
+                                    android:layout_width="wrap_content"
+                                    android:layout_height="wrap_content"
+                                    android:layout_marginStart="12dp"
+                                    android:text="@string/instruction_distractions"
+                                    android:textSize="16sp" />
+                            </LinearLayout>
+                        </LinearLayout>
+
+                        <Button
+                            android:id="@+id/btnDurationLabel"
+                            android:layout_width="180dp"
+                            android:layout_height="80dp"
+                            android:layout_marginTop="32dp"
+                            android:background="@drawable/btn_duration_selector"
+                            android:drawableEnd="@drawable/ic_keyboard_arrow_down"
+                            android:drawablePadding="8dp"
+                            android:gravity="center"
+                            android:includeFontPadding="false"
+                            android:paddingStart="16dp"
+                            android:paddingEnd="16dp"
+                            android:text="@string/start_timer"
+                            android:textColor="#FFFFFF"
+                            android:textSize="18sp"
+                            android:textStyle="bold"
+                            app:layout_constraintEnd_toEndOf="parent"
+                            app:layout_constraintStart_toStartOf="parent"
+                            app:layout_constraintTop_toBottomOf="@+id/instructionsLayout" />
+
+                        <HorizontalScrollView
+                            android:id="@+id/hsvDurationOptions"
+                            android:layout_width="wrap_content"
+                            android:layout_height="wrap_content"
+                            android:layout_marginTop="8dp"
+                            android:scrollbars="none"
+                            android:visibility="gone"
+                            app:layout_constraintEnd_toEndOf="parent"
+                            app:layout_constraintStart_toStartOf="parent"
+                            app:layout_constraintTop_toBottomOf="@+id/btnDurationLabel">
+
+                            <com.google.android.material.chip.ChipGroup
+                                android:id="@+id/chipGroup"
                                 android:layout_width="wrap_content"
                                 android:layout_height="wrap_content"
-                                android:minWidth="56dp"
+                                app:singleSelection="true">
-                                android:text="5s"
-                                app:chipBackgroundColor="@color/chip_duration_bg" />
 
-                            <com.google.android.material.chip.Chip
+                                <com.google.android.material.chip.Chip
-                                android:id="@+id/chip10s"
+                                    android:id="@+id/chip5m"
-                                style="@style/Widget.Material3.Chip.Suggestion.Elevated"
+                                    style="@style/Widget.Material3.Chip.Suggestion.Elevated"
-                                android:layout_width="wrap_content"
+                                    android:layout_width="wrap_content"
-                                android:layout_height="wrap_content"
+                                    android:layout_height="wrap_content"
-                                android:checked="true"
+                                    android:minWidth="56dp"
-                                android:minWidth="56dp"
+                                    android:text="5m"
-                                android:text="10s"
+                                    android:textColor="@color/chip_duration_text"
-                                app:chipBackgroundColor="@color/chip_duration_bg" />
+                                    app:chipBackgroundColor="@color/chip_duration_bg"
+                                    app:chipStrokeColor="@color/chip_duration_stroke"
+                                    app:chipStrokeWidth="2dp" />
 
-                            <com.google.android.material.chip.Chip
+                                <com.google.android.material.chip.Chip
-                                android:id="@+id/chip15s"
+                                    android:id="@+id/chip10m"
-                                style="@style/Widget.Material3.Chip.Suggestion.Elevated"
+                                    style="@style/Widget.Material3.Chip.Suggestion.Elevated"
-                                android:layout_width="wrap_content"
+                                    android:layout_width="wrap_content"
-                                android:layout_height="wrap_content"
+                                    android:layout_height="wrap_content"
-                                android:minWidth="56dp"
+                                    android:minWidth="56dp"
-                                android:text="15s"
+                                    android:text="10m"
-                                app:chipBackgroundColor="@color/chip_duration_bg" />
+                                    android:textColor="@color/chip_duration_text"
+                                    app:chipBackgroundColor="@color/chip_duration_bg"
+                                    app:chipStrokeColor="@color/chip_duration_stroke"
+                                    app:chipStrokeWidth="2dp" />
 
-                            <com.google.android.material.chip.Chip
+                                <com.google.android.material.chip.Chip
-                                android:id="@+id/chip30s"
+                                    android:id="@+id/chip15m"
-                                style="@style/Widget.Material3.Chip.Suggestion.Elevated"
+                                    style="@style/Widget.Material3.Chip.Suggestion.Elevated"
-                                android:layout_width="wrap_content"
+                                    android:layout_width="wrap_content"
-                                android:layout_height="wrap_content"
+                                    android:layout_height="wrap_content"
-                                android:minWidth="56dp"
+                                    android:minWidth="56dp"
-                                android:text="30s"
+                                    android:text="15m"
-                                app:chipBackgroundColor="@color/chip_duration_bg" />
+                                    android:textColor="@color/chip_duration_text"
-                        </com.google.android.material.chip.ChipGroup>
+                                    app:chipBackgroundColor="@color/chip_duration_bg"
-                    </HorizontalScrollView>
+                                    app:chipStrokeColor="@color/chip_duration_stroke"
+                                    app:chipStrokeWidth="2dp" />
 
-                    <View
+                                <com.google.android.material.chip.Chip
-                        android:id="@+id/spacerBelowChips"
+                                    android:id="@+id/chip30m"
-                        android:layout_width="1dp"
+                                    style="@style/Widget.Material3.Chip.Suggestion.Elevated"
-                        android:layout_height="5dp"
+                                    android:layout_width="wrap_content"
-                        android:layout_marginTop="8dp"
+                                    android:layout_height="wrap_content"
+                                    android:minWidth="56dp"
+                                    android:text="30m"
+                                    android:textColor="@color/chip_duration_text"
+                                    app:chipBackgroundColor="@color/chip_duration_bg"
+                                    app:chipStrokeColor="@color/chip_duration_stroke"
+                                    app:chipStrokeWidth="2dp" />
+                            </com.google.android.material.chip.ChipGroup>
+                        </HorizontalScrollView>
+
+                        <View
+                            android:id="@+id/spacerBelowChips"
+                            android:layout_width="1dp"
+                            android:layout_height="5dp"
+                            android:layout_marginTop="8dp"
+                            app:layout_constraintEnd_toEndOf="parent"
+                            app:layout_constraintStart_toStartOf="parent"
+                            app:layout_constraintTop_toBottomOf="@+id/hsvDurationOptions" />
+
+                        <FrameLayout
+                            android:id="@+id/btnStart"
+                            android:layout_width="100dp"
+                            android:layout_height="100dp"
+                            android:layout_marginTop="16dp"
+                            android:background="@drawable/btn_start_selector"
+                            android:clickable="true"
+                            android:focusable="true"
+                            app:layout_constraintEnd_toEndOf="parent"
+                            app:layout_constraintStart_toStartOf="parent"
+                            app:layout_constraintTop_toBottomOf="@+id/spacerBelowChips">
+
+                            <androidx.appcompat.widget.AppCompatImageView
+                                android:layout_width="match_parent"
+                                android:layout_height="match_parent"
+                                android:layout_gravity="center"
+                                android:contentDescription="Start"
+                                android:padding="20dp"
+                                android:src="@drawable/ic_play_arrow"
+                                android:tint="@android:color/white" />
+
+                        </FrameLayout>
+
+                    </androidx.constraintlayout.widget.ConstraintLayout>
+
+                    <!-- Countdown UI (initially hidden) -->
+                    <androidx.constraintlayout.widget.ConstraintLayout
+                        android:id="@+id/countdownLayout"
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:visibility="gone"
+                        app:layout_constraintBottom_toBottomOf="parent"
                         app:layout_constraintEnd_toEndOf="parent"
                         app:layout_constraintStart_toStartOf="parent"
-                        app:layout_constraintTop_toBottomOf="@+id/hsvDurationOptions" />
+                        app:layout_constraintTop_toTopOf="parent">
 
-                    <FrameLayout
+                        <com.example.countdowntimer.CountdownCanvasView
-                        android:id="@+id/btnStart"
+                            android:id="@+id/cvCountdown"
-                        android:layout_width="100dp"
+                            android:layout_width="0dp"
-                        android:layout_height="100dp"
+                            android:layout_height="0dp"
-                        android:layout_marginTop="16dp"
+                            app:layout_constraintDimensionRatio="1:1"
-                        android:background="@drawable/btn_start_selector"
+                            app:layout_constraintEnd_toEndOf="parent"
-                        android:clickable="true"
+                            app:layout_constraintStart_toStartOf="parent"
-                        android:focusable="true"
+                            app:layout_constraintTop_toTopOf="parent"
-                        app:layout_constraintEnd_toEndOf="parent"
+                            app:layout_constraintWidth_percent="0.9" />
-                        app:layout_constraintStart_toStartOf="parent"
-                        app:layout_constraintTop_toBottomOf="@+id/spacerBelowChips">
 
-                        <androidx.appcompat.widget.AppCompatImageView
+                        <LinearLayout
-                            android:layout_width="match_parent"
+                            android:id="@+id/buttonRow"
-                            android:layout_height="match_parent"
+                            android:layout_width="wrap_content"
-                            android:layout_gravity="center"
+                            android:layout_height="wrap_content"
-                            android:contentDescription="Start"
+                            android:layout_marginTop="24dp"
-                            android:padding="20dp"
+                            android:layout_marginBottom="24dp"
-                            android:src="@drawable/ic_play_arrow"
+                            android:gravity="center"
-                            android:tint="@android:color/white" />
+                            android:orientation="horizontal"
+                            app:layout_constraintBottom_toBottomOf="parent"
+                            app:layout_constraintEnd_toEndOf="parent"
+                            app:layout_constraintStart_toStartOf="parent"
+                            app:layout_constraintTop_toBottomOf="@+id/cvCountdown">
 
-                    </FrameLayout>
+                            <FrameLayout
+                                android:id="@+id/btnStop"
+                                android:layout_width="100dp"
+                                android:layout_height="100dp"
+                                android:layout_marginEnd="16dp"
+                                android:background="@drawable/btn_stop_selector"
+                                android:clickable="true"
+                                android:focusable="true" />
+
+                            <FrameLayout
+                                android:id="@+id/btnRestart"
+                                android:layout_width="100dp"
+                                android:layout_height="100dp"
+                                android:background="@drawable/btn_restart_selector"
+                                android:clickable="true"
+                                android:focusable="true" />
+
+                        </LinearLayout>
+
+                        <Button
+                            android:id="@+id/btnDismiss"
+                            android:layout_width="100dp"
+                            android:layout_height="100dp"
+                            android:layout_marginBottom="24dp"
+                            android:background="@drawable/btn_duration_selector"
+                            android:text="Dismiss"
+                            android:textColor="#FFFFFF"
+                            android:textStyle="bold"
+                            android:visibility="gone"
+                            app:layout_constraintBottom_toBottomOf="parent"
+                            app:layout_constraintEnd_toEndOf="parent"
+                            app:layout_constraintStart_toStartOf="parent"
+                            app:layout_constraintTop_toBottomOf="@+id/cvCountdown" />
+
+                    </androidx.constraintlayout.widget.ConstraintLayout>
 
                 </androidx.constraintlayout.widget.ConstraintLayout>
             </com.google.android.material.card.MaterialCardView>

app/src/main/res/layout/dialog_countdown.xml

@@ -1,83 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:app="http://schemas.android.com/apk/res-auto"
-    android:layout_width="match_parent"
-    android:layout_height="match_parent"
-    android:background="#80000000">
-
-    <com.example.countdowntimer.CountdownCanvasView
-        android:id="@+id/cvCountdown"
-        android:layout_width="0dp"
-        android:layout_height="0dp"
-        app:layout_constraintBottom_toTopOf="@id/buttonRow"
-        app:layout_constraintDimensionRatio="1:1"
-        app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toTopOf="parent" />
-
-    <LinearLayout
-        android:id="@+id/buttonRow"
-        android:layout_width="0dp"
-        android:layout_height="wrap_content"
-        android:layout_marginBottom="48dp"
-        android:gravity="center"
-        android:orientation="horizontal"
-        app:layout_constraintBottom_toBottomOf="parent"
-        app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent">
-
-        <FrameLayout
-            android:id="@+id/btnStop"
-            android:layout_width="100dp"
-            android:layout_height="100dp"
-            android:layout_marginEnd="16dp"
-            android:background="@drawable/btn_stop_selector"
-            android:clickable="true"
-            android:focusable="true">
-
-            <ImageView
-                android:layout_width="48dp"
-                android:layout_height="48dp"
-                android:layout_gravity="center"
-                android:contentDescription="@string/stop_timer"
-                android:src="@drawable/ic_stop_square" />
-
-        </FrameLayout>
-
-        <FrameLayout
-            android:id="@+id/btnRestart"
-            android:layout_width="100dp"
-            android:layout_height="100dp"
-            android:layout_marginStart="16dp"
-            android:background="@drawable/btn_restart_selector"
-            android:clickable="true"
-            android:focusable="true">
-
-            <ImageView
-                android:layout_width="48dp"
-                android:layout_height="48dp"
-                android:layout_gravity="center"
-                android:contentDescription="@string/restart_timer"
-                android:src="@drawable/ic_refresh_square" />
-
-        </FrameLayout>
-
-    </LinearLayout>
-
-    <Button
-        android:id="@+id/btnDismiss"
-        android:layout_width="100dp"
-        android:layout_height="100dp"
-        android:background="@drawable/btn_duration_selector"
-        android:gravity="center"
-        android:padding="16dp"
-        android:text="Dismiss"
-        android:textColor="#FFFFFF"
-        android:textSize="14sp"
-        android:textStyle="bold"
-        android:visibility="gone"
-        app:layout_constraintBottom_toBottomOf="parent"
-        app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent" />
-
-</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/values/strings.xml

@@ -1,12 +1,12 @@
 <resources>
     <string name="app_name">Countdown Timer</string>
     <string name="start_timer">Start Timer</string>
-    <string name="countdown_text">!!! HOLD !!!</string>
+    <string name="countdown_text">0</string>
-    <string name="timer_zero">EXHALE!</string>
+    <string name="timer_zero">AGAIN!</string>
     <string name="instruction_title">BONG HIT TIMER!</string>
-    <string name="instruction_volume">Light your bowl</string>
+    <string name="instruction_volume">When the timer elapses</string>
     <string name="instruction_position">Take your hit</string>
-    <string name="instruction_distractions">Press Start to time how long to hold it!</string>
+    <string name="instruction_distractions">Press Start to start the countdown to a bong load!</string>
     <string name="pick_duration">Pick Duration</string>
     <string name="settings">Settings</string>
     <string name="vibration">Vibration</string>

goal_prompt.txt

@@ -1,88 +0,0 @@
-# Goal: Redesign all buttons into bold, square, visually striking interactive elements
-
-## Objective
-Replace every basic/rectangular button in the app with larger, square-aspect-ratio buttons that have eye-catching visual design. The goal is to transform the UI from a generic Material 3 look into a distinctive, personality-rich interface that matches the playful "BONG HIT TIMER" brand.
-
-## Current State
-The app uses 4 visible buttons across 2 screens:
-
-**MainActivity (home screen):**
-- `btnDurationLabel` — outlined button showing selected duration (e.g. "10s") with a dropdown arrow. Uses `Widget.Material3.Button.OutlinedButton` with 20dp corners.
-- `btnStart` — filled button labeled "Start Timer" with a play icon. Uses `Widget.Material3.Button` with 20dp corners.
-
-**CountdownDialog (timer screen):**
-- `btnStop` — plain Android `Button` labeled "Stop" (default styling, small)
-- `btnRestart` — plain Android `Button` labeled "Restart" (default styling, small)
-- `btnDismiss` — plain Android `Button` labeled "Dismiss" (currently gone, shows after timer completes)
-
-## Design Requirements
-
-### 1. Square Aspect Ratio
-- Change all buttons from `wrap_content` rectangles to a fixed square size (e.g., `120dp` x `120dp` or `100dp` x `100dp`)
-- Use `app:layout_constraintDimensionRatio="1:1"` where dynamic sizing is needed
-- Buttons should feel substantial and tappable, not compact
-
-### 2. Visual Interest — Each button should have its own personality
-Create custom drawable backgrounds for each button type. Design ideas (pick the best approach):
-
-- **Circular/spherical buttons** — Buttons that look like physical 3D balls or pucks. Use gradient fills with highlights/shadows to create a convex "pressable" look.
-- **Neon/glow effect** — Since the app is a bong hit timer, a subtle neon glow that pulses or intensifies during countdown would be thematically appropriate.
-- **Retro/gaming arcade style** — Bold colors, thick borders, pressed/active states that simulate physical button depression.
-- **Gradient + icon centering** — For the timer screen, center the stop/restart icons prominently in the square buttons with bold gradient backgrounds.
-
-### 3. Interactive States
-Every button must have rich feedback:
-- **Pressed/active state** — noticeable visual change (shrink, darker shade, or inner glow)
-- **Default state** — visually engaging with gradients, shadows, or subtle animations
-- **Disabled state** — reduced opacity but still recognizable
-
-### 4. Icon Integration
-Square buttons are perfect for icon-first design:
-- **Stop button** — large centered pause/stop icon
-- **Restart button** — large centered refresh/replay icon
-- **Start button** — center the play icon, consider removing the text label since the icon is universal
-- **Duration label** — consider a pill-shaped or circular chip that pulses when tapped
-
-### 5. Color Palette
-Stay within the existing green theme (`#2E7D32` primary, `#4C6842` secondary, `#E8F5E9`/`#C8E6C9` gradient) but push it further:
-- Use the primary green for the start/positive actions
-- A red/coral accent for stop
-- A neutral or blue for restart/duration selection
-- Consider gradient transitions within each button (e.g., green to darker green top-to-bottom for a 3D effect)
-
-### 6. Shadow & Elevation
-- Add drop shadows to all buttons for depth (use `app:strokeWidth="0dp"` and custom `rippleColor` for Material buttons)
-- Create a `btn_square_default.xml` and `btn_square_pressed.xml` in `res/drawable/` for each button type
-- The pressed state should visually simulate "pressing in" (reduced shadow, lighter/darker fill)
-
-## Technical Implementation
-
-### New drawable files to create (in `res/drawable/`):
-- `btn_start_square.xml` — gradient + shadow drawable for start button
-- `btn_start_square_pressed.xml` — pressed state variant
-- `btn_stop_square.xml` — gradient + shadow drawable for stop button
-- `btn_stop_square_pressed.xml` — pressed state variant
-- `btn_restart_square.xml` — gradient + shadow drawable for restart button
-- `btn_restart_square_pressed.xml` — pressed state variant
-- `btn_duration_chip.xml` — drawable for duration selector
-
-### Layout changes needed:
-- `activity_main.xml`:
-  - `btnDurationLabel`: change to square dimensions, wrap text/icon in center, apply new drawable
-  - `btnStart`: change to square, center play icon, apply new drawable
-- `dialog_countdown.xml`:
-  - `btnStop`: change from `Button` to `com.google.android.material.button.MaterialButton`, set square dimensions, apply drawable
-  - `btnRestart`: same treatment
-  - `btnDismiss`: same treatment, keep as gone by default
-  - Adjust the ConstraintLayout chain to accommodate square buttons (may need a horizontal chain with proper spacing)
-
-### Code changes needed:
-- `CountdownDialog.kt`: Set button backgrounds programmatically if needed, ensure clickable/pressable states work
-- No changes to button click logic — only visual overhaul
-
-## Constraints
-- Use only Material 3 components already in the dependency (`com.google.android.material:material:1.11.0`)
-- Traditional XML layouts — no Compose
-- Minimum SDK 24 — no API 30+ features
-- Keep the app's existing green aesthetic but make it bolder
-- Maintain accessibility (minimum 48dp touch target, sufficient contrast)