GR translation: soft, nearly invisible in the December-dawn enclosure

[Mike Jing]

V125.32-34, P128.4-7   He was taken over then, for half a minute, shivering
and yawning in his long underwear, soft, nearly invisible in the
December-dawn enclosure, among so many sharp edges of books, sheafs and
flimsies, charts and maps

Does "soft, nearly invisible in the December-dawn enclosure" describe his
underwear?