:root{
--shadow-sm:0 1px 2px rgba(0,0,0,0.04);
--shadow-md:0 2px 4px rgba(0,0,0,0.06);
--shadow-lg:0 4px 12px rgba(0,0,0,0.08);
--shadow-focus:0 0 0 2px rgba(37,99,235,0.30);
}