visual enhancements and documentation changes.

CLAUDE.md

@@ -7,13 +7,13 @@
 - **Run Unit Tests**: `./gradlew test` (if applicable)
 
 ## Code Style Guidelines
-- **Language**: Kotlin 1.9+
+- **Language**: Kotlin 1.9.0
 - **UI Framework**: Traditional Android View system (XML layouts), **not** Jetpack Compose.
 - **Naming Conventions**:
   - Classes: `PascalCase` (e.g., `CountdownDialog`)
   - Functions/Variables: `camelCase` (e.g., `startTimer()`)
   - Layout Files: `snake_case` (e.g., `activity_main.xml`)
-  - Resource IDs: `snake_case` (e.g., `btn_start`)
+  - Resource IDs: `camelCase` (e.g., `btnStart`, `cvCountdown`)
 - **Android Patterns**: Use `findViewById` for view binding in this project to maintain consistency with existing simple architecture.
 
 ## Architecture
@@ -26,6 +26,7 @@
 ## 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/CountdownDialog.kt`: Implementation of the countdown logic and `ToneGenerator` trigger.
+- `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/dialog_countdown.xml`: Timer dialog layout.
 - `app/build.gradle`: Build configuration, SDK versions (minSdk 24, targetSdk 34), and dependencies.