I don't understand why the website header's links aren't jumping to the proper part of the page?

My website is kristyelee.github.io. I don't know why clicking "About" or "Projects" or etc doesn't cause the page to jump to the right place; instead the page jumps to midway between one section and "About" or midway between one section and "Projects." I need help debugging this. (Please view on desktop). Thanks.