Struggling with Webflow :(

I’ve watched some of the Webflow university tutorials such as the Responsive Design guides and the Webflow Masterclass courses and I’m still having a tough time building my portfolio – super frustrating.

I’m having a really tough time editing the desktop, tablet and mobile screens. When making changes to the tablet view, it messed up my desktop view. In the tablet view under the “section_background”, I can’t remove the extra white space between the header and the paragraph using flexbox Also, I’m trying to edit the nav menu in the tablet to look like this:, but when I add a bottom border, it adds a border around the entire text block. Not sure if there are some minor bugs in the editor or if I’m doing something wrong. Since I don’t have a strong background in coding, it’s taking me a while to get the hang of this.

Here is my site Read-Only: LINK
(how to share your site Read-Only link)