What is the antecedent in this passage?

sample taken from a Toefl exam

Just as painted designs on Greek pots may seem today to be purely decorative, whereas in fact they were carefully and precisely worked out so that at the time, [sic] their meaning was clear, so it is with Chinese pots.

(langlib.com)

Hi everybody, my question is about the antecedent of "it", and what is the reference of "was"?

Solution 1:

I am distilling down the verbiage in each example, and actually rephrasing things a bit in the second in order to get it to express its essential meaning in a shorter fashion.

1. It.

Just as designs on Greek pots seem decorative, so it ^{(designs seeming decorative)} is with Chinese pots.

2. Their / was.

Although designs on Greek pots may seem decorative ^{(without meaning)} today, their ^{(the designs on Greek pots)} meaning was clear ^{(when the pots were created).}

Solution 2:

The subject of was is meaning.

It refers to the entire language before so, as @BillJ says in his comment.

As you can tell from comments, the punctuation is poor. It would have been better as two sentences. The writer is trying to say that what’s true of Greek pots is also true of Chinese pots.