CSS shape with inset curve and transparent background

Question

I need to create a CSS shape like this image..

Please check this fiddl

Answer 1

You can use a pseudo element with border-radius and background-shadows to create the curve and enable a transparent background for the curve.

Output :

#shape {
  width: 300px; height: 100px;
  position: relative;
  overflow: hidden;
}

#shape:before {
  content: '';
  position: absolute;
  top: 10%; right: 0;
  width: 300%;
  padding-bottom: 300%;
  border-radius: 100%;
  background: none;
  box-shadow: 10px -10px 5px 300px #F15723;
  z-index: -1;
}

body{background:url(https://farm9.staticflickr.com/8461/8048823381_0fbc2d8efb.jpg);background-size:cover;}

demo