The Purpose margin stack was the PDF's TikZ stack compiled to SVG and shown at
100% of the margin column: a 250x540 tower in vol1 and vol2, unreadable
6-point text in vol3, and a white card in dark mode. Generate it natively
instead, about 220px wide and 130-200px tall, with real text, each volume's
layers and accent, and the chapter's weights still read from the PDF macro
call. One focus tile marks the chapter's top weight; even weights stay flat.
Tiles are the accent at partial opacity on a transparent background, so the
image sits on the page without a card and dark mode inverts it with the hue
held. The generator only writes SVGs; the old one rewrote chapter files and
would have duplicated the HTML block on a rerun.
Vijay Janapa Reddi