how to make inside border-radius in css?

Question

How can I make the border radius towards inside?

.circle {
   width:100px;
   height:100px;
   background-color:solid red;
   border-radius:-50px 50px -50px [ent         


        

Answer 1

SVG

You should not use css to create complex shapes.
Use SVG instead.

Shape created with a SVG Path
In addition to 3 curves in the path

Highlighted each curve so you can see how to create the final shape.