body {
  font-family: sans-serif;
  margin: 30px auto;
  text-align: center;
  background: #eee;
}
.actions {
  margin: 20px 0;
}
.button,
button {
  padding: 10px 20px;
  border: 2px solid black;
  background: #fff;
  font-size: 1em;
  text-decoration: none;
  color: #000;
  line-height: 1;
  display: inline-block;
}
.button:hover,
button:hover {
  background: #000;
  color: #fff;
  cursor: pointer;
}
.button[disabled=true] {
  opacity: 0.6;
  pointer-events: none;
}
#c {
  background: #fff;
  box-shadow: 0 2px 16px rgba(0,0,0,0.2);
}