<button></button>

body {
	display: flex;
	justify-content: center;
	margin: 0;
	height: 100vh;
}

button {
	align-self: center;
	border: solid .25em transparent;
  padding: .25em;
  width: 10.75em; height: 4em;
  border-radius: 1.375em;
  box-shadow: inset 0 1px 1px rgba(#f7f7f7, .875), 
    inset 0 -1px 1px rgba(#bbb, .75);
  background: 
		radial-gradient(#{at 8.5em calc(50% - 2.625em)}, #f7f8fa, transparent .625em), 
		radial-gradient(circle at 8.5em 50%, 
        #afafaf .625em, #ccc calc(.625em + 1px), 
        #ccc .75em, rgba(#ccc, 0) calc(.75em + 1px)),
		linear-gradient(#9ea1a6, #fdfdfe) content-box, 
    linear-gradient(#fff, #9c9fa4) padding-box, 
    linear-gradient(#eee, #a4a7ab) border-box;
	background-size: 100% 225%, 100%, 100%, 100%, 100%;
}