My HTML webpage is not loading and keep disappearing after it load for split second

[JustinLRT]

I searched on Google on how to preview my HTML and i found an information that to preview HTML files on GitHub is to visit https://htmlpreview.github.io then put the GitHub link of homepage.

But this is NOT WORKING to me. Instead, they load the page WITHOUT CSS styles and then now shows blank page. I tried to refresh so many times until I see the actual page with CSS styles I applied. I checked my code and it's fine and it's perfectly works in my phone and in other phones by apps and browsers and even the 'file://' in browser URL and it's perfectly works!

In some pages in my repositories, it load once and it's fine (no issues), but in some like navigation page, homepage, Manila LRT articles are showing WITHOUT CSS STYLES then after split seconds then it shows blank page.

This is the video for your reference: https://youtu.be/KO_ZJI5j7DI

This is a link for previewing: https://htmlpreview.github.io/?https://github.com/JustinLRT/website/blob/main/home.html

This is my repository: https://github.com/JustinLRT/website/