Worked on the apache/poi repository to address styling consistency across document formats, focusing on stabilizing style propagation and inheritance mechanisms. Delivered a targeted bug fix that ensured row styles set in XSSF and SXSSF propagate correctly to cells, while also enhancing HSSF style inheritance so unstyled cells reliably fall back to column or row styles. Improved the test infrastructure by refactoring XSSF tests to use try-with-resources and cleaning up formatting and static assertions, which reduced test flakiness and improved maintainability. Utilized Java, JUnit, and software testing best practices to deliver changes that reduce support overhead and improve document rendering consistency.