I can't remove gap between my sections

[mauthoor010203]

There are some white gaps between my sections and I tried margin and padding but it doesn’t seem to work. Also, my tiles appear blurry and I don
't know to fix that. I used screenshots of my work and I was thinking that the resizing is what caused the blurriness. There’s also a gap between the title and the picture in the projects section which margin and padding didn’t fix also. Am I targetting the wrong element or something?

Your code so far

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User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.63 Safari/537.36

Challenge: Build a Personal Portfolio Webpage

Link to the challenge:
https://codepen.io/Motasim0109/pen/rNwjNjz?editors=1100

[adramelech]

It is caused by the margin of h2

I prefer a global reset before anything on css

*,*::after,*::before{
  margin:0;
  padding:0;
  box-sizing:border-box
}

or you can remove the margin top of h2 specifically

h2{
    margin-top:0;
}