hi sir, I have read your project description but the kind feature/effect you would like in your website (and be able to make changes in it by yourself in the future) is possible in WordPress, not in HTML/CSS. So please discuss on chat if you are willing to go with WordPress so I can build it for you.
I have been doing similar tasks as well as developing full fetched websites in WordPress, html, css, js, jquery and boostrap, having more than 5 years of experience.
Please leave me a message if you are interested.