Fix tooltip overflow on long text (picocss/pico#665, picocss/pico#715).

- Add white-space: normal and max-width: 20rem on tooltip pseudo-element.
- Update CLAUDE.md with new PicoCSS override reference.

Author: Amaury

CLAUDE.md

@@ -56,5 +56,6 @@ These µCSS rules exist to fix PicoCSS default behaviors:
 - `li ul, li ol { margin-bottom: 0 }` — Fix nested list extra margin (picocss/pico#672) — remove when fixed upstream
 - `nav details.dropdown { display: inline-block }` — Fix Firefox full-width nav dropdowns (picocss/pico#701) — remove when fixed upstream
 - `:where([role=group], [role=search]) + small` — Fix helper text not styled after input groups (picocss/pico#540, picocss/pico#700) — remove when fixed upstream
+- `[data-tooltip]::before { white-space: normal; max-width: 20rem }` — Fix tooltip overflow on long text (picocss/pico#665, picocss/pico#715) — remove when fixed upstream
 - PicoCSS sets `:where(table) { width: 100% }` — all tables are fullwidth by default, no `.table-fullwidth` class needed
 - PicoCSS `.outline` button style (3 colors) coexists with µCSS `.btn-outline` (11 colors) — different selectors, no conflict

css/mu.utilities.css

@@ -23,6 +23,12 @@ li ol {
 	color: var(--mu-del-color);
 }
 
+/* PicoCSS bugfix: tooltips overflow on long text (picocss/pico#665, picocss/pico#715) — remove when fixed upstream */
+[data-tooltip]::before {
+	white-space: normal;
+	max-width: 20rem;
+}
+
 /* Positioning */
 
 .sticky-top {