Here’s some feedback from me
You might wanna tighten the width of the page, it’s really hard to read as it is now.
Here’s a post about balancing line length/font size in responsive web design. So usually you want to aim between 45-75 characters per line, more then that causes fatigue.
Also adding some padding or margins between the elements (title, subtitle, image, text paragraph, footer) would help to improve the site visually and easier to read. Another suggestion is to try and play with font sizes on some elements, for an example try to set a bigger font for the quote “It was the best of times, it was the worst of times…”.
The footer is also very hard to read, you might wanna think of a solution for that also.
The text is a bit hard to read on the current background,
Also again maybe you could try to play with the padding/margins here. So when you click “About” in the sidebar that it displays only the “About” part, without the portfolio.
But overall I think that the technical parts of your websites are very good, you might wanna just improve the visuals a bit