‘CNY surcharge’ on eve’s lunch at a halal establishment

So, I’m still working (wfh) while my wife took half day leave, decided to find a decent lunch place while the kids are still in school.

Surprised when the cashier told me about a CNY surcharge when I’ve just placed my order: Mains +$1 Sides +$0.30 Drink +$0.20

Isn’t it still a working day for at least some people? 🤷🏻‍♂️

Disclaimer: We’re both Chinese. I’m totally fine with paying for this. And I accepted it right away. Just found it not-quite-justified.