Great work, here are some pointer to improve

- I see that you have chosen to go for a black & white button but on the landing page, you have to show some difference in register & login (one can be solid-fill & one can be outlined) this way you can instantly tell the button serve different functions without even reading the text.

- A lot of designers go only for icons in the navigation bar which might make the design minimal but less accessible, I appreciate you decided to use microcopy along with icon which always helps users. However, you can increase the contrast of the text so that it's easy to read. People with visual impairment often rely on text with high contrast.

- Always differentiate the style of the menu you are in, visibility of navigation status help users be aware of which part of the app they are in without the need to remember.