@import url(http://fonts.lug.ustc.edu.cn/css?family=Source+Sans+Pro:300,400,600);

* {
  box-sizing: border-box;
  margin: 0;
  border: 0;
}

html, body { height: 100%; }
body {
  display: flex;
  justify-content: center;
  align-items: center;
  background: whitesmoke;
}

button {
  font-family: Source Sans Pro;
  font-size: 1rem;
  line-height: 3.5em;
  padding: 0 1.5em;
  background: gold;
  box-shadow: inset 0 -.125rem rgba(0,0,0,.2);
  color: black;
  border-radius: 5em;
  cursor: pointer;
  user-select: none;
  transform-origin: 100% 100%;
  
  &:focus { outline: 0; }
}

.shadow {
  margin-top: -.325rem;
  width: 100%;
  height: .75rem;
  background: radial-gradient(closest-side, gainsboro, transparent);
  opacity: 0;
}