I read this in Word by Word by Kory Stamper:
Nowhere else is our institutional introversion borne out than at the Merriam- Webster holiday parties. The parties are usually held in the afternoon, in the basement of the building, which in some years is literally spruced up for the occasion.
I want to ask why the writer is emphasising "spruced up" with "literally". I mean what would "spruced up" metaphorically imply.