GeezerVison

bug (medium): --color-clay isn't defined anywhere (the :root brand tokens only have paper/card/sink/shell/stone/ink/violet/onyx/moss/change*). var() with no fallback makes this invalid at computed-value time, so background falls back to transparent: in Safari the thumb disappears on hover instead of turning Clay. Add the token to :root, or use an existing one.

pitfall (medium): scrollbar-color is an inherited property, and since Chrome/Edge 121 any element whose computed scrollbar-color/scrollbar-width isn't auto ignores ::-webkit-scrollbar*. Setting it on html passes it down to every element, .theme-code-block pre included. So in current Chrome/Edge, the 8px square thumb, the Clay hover and the faint code-block thumb (L438-445) never apply. Code blocks get a Stone thumb on the dark background instead. Only Safari uses the webkit block. To fix, give the code blocks their own standard rule (.theme-code-block pre { scrollbar-color: rgb(250 249 246 / 0.2) transparent; }), and accept that Chromium shows no hover or square-thumb styling, or stop setting the standard props on html in Chromium.