I have a web site: www dot my-portfolio-site.site88 dot net/ and I want that the website has to be responsive and perfectly function on mobiles and tablets.

For your kind information, I know HTML and CSS coding. But I donít know how to convert the website has to be responsive and perfectly function on mobiles and tablets.

So, please see my source code and suggest which code I should write. And where should I place it?
No more, I am waiting for your kind response.

Thank you.