Custom design according to image

Question

I want to create something like the image shows.
Imagine this as the background of the website that above this there will be anything else like h1 tags inputs etc.
Which is the best way to accomplish that?
With only use of code?
Or with background image? And if so, what about the large screens?

Answer 1

It can work for you..!

.curved {height: 130%; width: 100%; position: fixed; top: -15%; left: -50%; background: #5779aa; border-radius: 10%/50%; z-index: -1;}

<divc class="curved">

</div>