Curved Sections

I have been improving on my html and css skills while learning to code js. and its been a really fun journey so far. 🙌

Though this challenge was quite tough in the beginning as I always had problems in background images but after completing this one I have gain some confidence in the same.😎

But there is question that I have for the community that I been wondering about for quite some time, that is how to size and position the elements as given in the screenshots. I always mess this up.😅

I would like to get some feedback on the same, that is how you manage getting the sizes and position accurate🤓.