After some trials and errors, I finally got the right answer to set up my Disqus commenting system at

https://stackoverflow.com/questions/41613661/we-were-unable-to-load-disqus-with-jekylls-default-minima-theme#41614249

I have thought about using the GitHub commenting system according to

GitHub Comments for your GitHub Pages

, but my topics on buildings and thermal systems are related to people without GitHub accounts, right? So I opt for Disqus at the end. Hope it’s slowness and third-party page link won’t bother you too much =D