:root{
/* flat-first system: hairline borders and surface alternation carry depth, not shadow.
   shadow-sm/md are reserved for transient overlays (dialogs, dropdowns, toasts) only — never cards. */
--shadow-none:none;
--shadow-sm:0 1px 3px oklch(0.2 0.02 40 / 0.10);
--shadow-md:0 8px 24px oklch(0.2 0.02 40 / 0.14);
}