Visualize Data with a Heat Map
A heat map visualizes monthly global temperature variances from 1753 to 2015, using blue color intensity to show deviations from the base temperature. The visualization is built with the Vega-Lite API, specifically using the `markRect` encoding function with data from the freeCodeCamp ProjectReferenceData JSON. It employs ordinal axes for year and month, and a quantitative color scale with a blues scheme. Tooltips display year, month, and variance values. The project integrates D3.js, Vega, and Vega-Lite libraries, with a custom dark theme configuration for improved readability.