Github pages is not showing my CSS

I’m using github pages to test and host my website, but github pages is only showing half of my CSS.
I’m relatively new to github, and I’m wondering if I did something wrong.

this is the link to my code. Would be a big thanks if I could get help.

I’m not very sure of this but

Note: The inline styles have the highest priority, and the external style sheets have the lowest. It means if you specify styles for an element in both embedded and external style sheets, the conflicting style rules in the embedded style sheet would override the external style sheet.