Well, it's possible that my confusion is associated with the fact that I don't come from an English-speaking country, the fact is that I don't understand the meaning of the theme "A Matter of Degree". It is very difficult for me to take an interpretation of it because I do not know what it refers to. I would appreciate it if I could be given some information. Thank you in advance.

This forum thread might be helpful:

https://forum.wordreference.com/threads/matter-of-degree.3240353/

This post in particular:

"It's a matter of degree" means "It depends on how much..."

It's raining? That's really bad.

Well, not necessarily, because we needed some rain for the crops. It's a matter of degree: too much rain at this time of year would spoil the grape harvest.

I picked this theme because you could interpret it many ways. Here are some suggestions:

• in a way related to the idiomatic expression
• temperature (degrees)
• angles (degrees)
• a title from a university or other postsecondary education (a degree)
• physics and gravity (matter)

someone on twitter joked about making a game about deodorant because of the brand "Degree" and I consider that valid! 

My interpretation is analogous to another idiom of similar Spirit: "a matter of time". Since time is also measures by degrees, (seconds, minutes, et al...) it felt appropriate.

Lin Ji.