Developed a character-by-character highlighting feature for partial word translation in the koreader/koreader repository, focusing on enhancing text selection precision within the user interface. The implementation introduced a move_by_char mode in the highlight dialog, which users can toggle via long-press gestures on edit controls, demonstrating skills in frontend and UI development. Built using Lua, the feature enables finer segmentation of text for translation, improving workflow accuracy and accessibility. The work was delivered incrementally with clear commit history and aligned with pull request review processes, laying a foundation for future advanced translation capabilities without addressing critical bugs during the development period.