Worked on the electricitymaps-contrib repository to address a chart rendering issue affecting the midnight marker’s visibility and alignment across devices. Focused on front end development using React, JavaScript, and TypeScript, the solution involved adjusting the vertical positioning of the marker to ensure it remained visible and correctly extended across varying chart heights, particularly on mobile. This fix improved the reliability and readability of time-based visualizations, reducing user confusion and potential support requests. Demonstrated careful change management by reverting an incorrect branch change to maintain stability, and maintained a clear, disciplined commit history to support quality assurance and release readiness.