Spacing issues Portfolio project

I’ve been having a ton of issues with layout and spacing in this project and have resigned myself to just getting it to look decent and pass the tests. My current issue is that there’s too much space between each section but it doesn’t show that way in the editor, only in the full page view. When I start reducing margins and trying other things to lessen the gaps between sections, the elements start overlapping in the editor viewport. Does anyone have any ideas about this? In the course of working on this project I did learn about the clearfix hack and am wondering if this might be a solution? But if so, not sure exactly where in the CSS it should be applied.
Link to my pen https://codepen.io/rosiegk/pen/gOxXNQd

In the welcome section you have added 100vh
and below sections have padding+margin
adjust and see if it works.

#welcome-section {
  height: 50vh;
  width: 90%;
  margin: 0px 50px 0px 50px;
}