This interactive 100% stacked bar chart visualizes the distribution of sleep disorders (None, Insomnia, Sleep Apnea) across binned stress levels for a synthetic "Sleep Health & Lifestyle" dataset, with a gender filter and clickable legend. Built with D3 v7 and React, the visualization computes proportional segments per stress bin, using an ordinal color scale and animated transitions via `transition().duration()` to update bars when the gender select changes. Hovering a segment reveals a tooltip with exact percentages and category counts, while the legend filters which disorder categories are displayed.