Text falls back to the right font

When a page's first-choice font isn't available, the engine now walks the page's own list of fallbacks to the next real font - usually the system font - instead of dropping to a generic Arial-like stand-in, so nav bars, menus, and headings match what other browsers show. It also renders heavy text at a font's real weight instead of a faked thickening, and correctly loads variable web fonts that declare a whole range of weights.