I have primarily focused on the application layer of Android development, but I have also had the opportunity to work on system UI components, such as customizing the main action bar and top bar. These experiences have provided me with a solid understanding of the Android system architecture and its interaction with hardware. 

One challenge I faced was ensuring that these customizations were both efficient and compatible across various devices. This required a thorough exploration of the Android framework and close collaboration with hardware teams to achieve seamless integration. 

I am excited to expand my expertise into full platform development and believe that my background in application-level customizations and system UI components has prepared me well for this transition.