Cards adapt automatically — `_cards.scss` rotates the card header inside any `.pa-splitter__pane--minimized` without needing the attribute. No markup change needed for the card snippets above. CSS CUSTOMIZATION --pa-splitter-gutter-size gutter thickness (default: 6px) --pa-splitter-rail-size rail width when a pane is minimized (default: 40px / $splitter-rail-size). JS picks this up via getComputedStyle, so setting it on `:root` or per-instance via inline style overrides the rail width without also setting the data-attr. gap space between panes and gutter (native flexbox property) MODIFIER CLASSES pa-splitter--minimize-mirror flip the minimized title 180° (transform: scale(-1,-1) on the heading inside any `[data-pa-splitter-rail-title]` or `.pa-card__header`) JAVASCRIPT API (window.PaSplitter) PaSplitter.init(el) initialize a single element (idempotent) PaSplitter.initAll(root?) initialize all uninitialized splitters under root (default: document) ================================ -->