Literature Reference: 玄帷隔雪风，照炉钉明釭。—— 《病中赠张十八》 The dark curtain shields the snowy wind, while the stove's light nails the bright lamp. Source from 'Bing Zhong Zeng Zhang Shiba'.
玄: Cultivated and erudite.
帷: The curtain. The drapery. He stood facing west, drawing back the curtain.—"Records of the Grand Historian: Annals of Xiang Yu"
Meaning: The dark curtain symbolizes mystery and depth.