How can I draw the following background image?

CodePudding user response：

conic-gradient, mask and pseudo element

html:before,
html:after {
  content: "";
  position: fixed;
  aspect-ratio: 1;
  width: 130%;
  left: -40%;
  bottom: 20%;
  border-radius: 50%;
  border: 20px solid green;
  -webkit-mask: conic-gradient(#000, #0000 65%);
}

html:after {
  transform: translate(15%);
}