Worked on the ebayui-core repository to deliver a security-focused upgrade of the Highcharts library, moving from version 11.3.0 to 11.4.8. This update addressed known security vulnerabilities and improved compatibility with the latest Highcharts API. The work involved refining TypeScript typings to distinguish color handling between bar and area chart series, ensuring more robust and maintainable chart components. By updating interface definitions and aligning them with new Highcharts types, the changes reduced technical debt and streamlined future upgrades. Leveraging expertise in front-end development, chart libraries, and UI components, the developer established a stronger foundation for ongoing chart enhancements and maintenance.