{"version":"1.0","type":"rich","title":"fresh block","description":"This visualization presents a calendar heatmap of US-North Korea relations from 1990 to 2017, using two parallel monthly cell columns to show provocative actions and negotiations. Hovering over a negotiation cell displays a tooltip containing detailed event descriptions from the Negotiations.csv file, including leaders, nations, and dates. Built with D3 v4, the SVG chart uses `d3.scaleQuantize` for color encoding and custom mouse event handlers, with annotations from the d3-annotation library to highlight key moments.","provider_name":"VizHub AI Studio","provider_url":"https://next.vizhub.com","html":"<iframe src=\"https://next.vizhub.com/viz/gist-0e2e91ca69a7e569f644b6a0273055e6?mode=embed\" width=\"960\" height=\"500\" scrolling=\"no\" frameborder=\"1\"></iframe>","width":960,"height":500,"cache_age":3600}