/* ── Dark mode — MOBILE ONLY (2026-09-14) ────────────────────────────────── Palette "B — Slate", picked from /darkmode-test.html: the literal inversion of the light theme, keeping #DCDCE3's faint blue-violet cast. How it switches: an inline script at the very top of every page's sets from localStorage.theme BEFORE first paint, and the burger menu's Hell/Dunkel toggle (/theme/theme.js) flips it live. The nav iframe links this same file and follows along on its own. Everything below sits inside the 640px query on purpose — "mobile only for now". A desktop window, or a phone rotated past 640px, ignores the attribute and renders the light theme. This is also the burger menu's breakpoint, so the toggle and the theme it controls exist at exactly the same widths. This file is ed AFTER each page's own