Last-resort system font fallback

House — بيت

body declares only font-family: serif, which has no Arabic glyphs, and "RegisteredArabic" is never referenced by any font-family value - it is registered on the page purely via @font-face. Because no declared family covers "بيت", PeachPDF searches every OTHER font it knows about and finds it there, instead of drawing missing-glyph boxes.