Arthur Evain focused on improving accessibility in the lichess-org/lila repository by addressing a UI issue affecting blindfold chess mode. He implemented a targeted CSS fix using SCSS to override opacity settings, ensuring that promotion pieces remained fully visible in the promotion chooser. This solution resolved a visibility gap that previously hindered user experience for blindfold players. Arthur validated the patch across all relevant promotion flows to prevent regressions, demonstrating careful frontend debugging and disciplined version control. His work, though limited to a single bug fix during the period, contributed to a more accessible and user-friendly interface for the chess platform.