Why is the site displayed incorrectly on github.io hosting?

Question

css

The site displays well on local hosting, but when publishing a github repository on GitHub Pages, individual media expressions and the tag do not work <picture>, for example. Moreover, the same code can be displayed correctly in the header, but incorrectly in the footer.

Answer 1

I have a vague doubt that these "separate media expressions" and picture use http instead of https.

Answer 2

You can install ruby ​​gem github-pages locally and debug. You may be using jekyll plugins that are not included on github.