I’m not sure if I can give advice, but I can refer you to Joshua Fluke on YouTube, he has a lot of content about this kind of stuff and can help out with the portfolio.
You definitely need to minimize and manage the font size for mobile version especially for header and footer part .
I don’t think there’s any need for that black border after every section. Also , give each section a proper title and description for easy navigation .
You have some language problems on your site. I would ask a native speaker to look it over and make corrections if you are planning to use it for professional purposes.
The last item in your menu is cut off.
If you can, get an email address with a custom domain (i.e. your name) instead of a Gmail address. It looks more professional.