What does その中に mean in this sentence?

[sergiop]

… 輪郭の柔らかな瓜実顔をその中に横たえている。

“… framing the soft outlines of her oval face.”

I’m confused, what その中に means in the context of this sentence fragment? Thanks for any help.

[YukiPhoenix]

その中 is an adverb expression meaning something like therein or wherein.

JapanDict: Japanese Dictionary - Definition of その中

Here’s also a weblio link that has some example sentenced using this:

「その中」の英語・英語例文・英語表現 - Weblio和英辞書

その中に横たえている

To answer more specifically, this part of the sentence means something like “laying down in it” or “laying down in the middle of it” in reference to where her face is placed. その being a reference to her 長い髪 (long hair) which I presume comes from this sentence I found on HiNative?

女は長い髪を枕に敷いて、輪郭の柔らかな瓜実顔をその中に横たえている。