.pulse:hover,
.pulse:focus {
  -webkit-animation: pulse 1s;
          animation: pulse 1s;
  box-shadow: 0 0 0 2em rgba(255, 255, 255, 0);
}

@-webkit-keyframes pulse {
  0% {
    box-shadow: 0 0 0 0 var(--hover);
  }
}

@keyframes pulse {
  0% {
    box-shadow: 0 0 0 0 var(--hover);
  }
}

.raise:hover,
.raise:focus {
  box-shadow: 0 0.5em 0.5em -0.4em var(--hover);
  transform: translateY(-0.25em);
}

.pulse {
  --color: #ef6eae;
  --hover: #ef8f6e;
}

.raise {
  --color: #ffa260;
  --hover: #e5ff60;
}

button {
  color: var(--color);
  transition: 0.25s;
}
button:hover, button:focus {
  border-color: var(--hover);
  color: #fff;
}

body {
  color: #fff;
  background: #17181c;
  font: 300 1em "Fira Sans", sans-serif;
  justify-content: center;
  align-content: center;
  align-items: center;
  text-align: center;
  min-height: 100vh;
  flex-direction: column;
  display: flex;
}

button {
  background: none;
  border: 2px solid;
  font: inherit;
  line-height: 1;
  margin: 50px;
  padding: 1em 2em;
}

h1 {
  font-weight: 400;
}

code {
  color: #e4cb58;
  font: inherit;
}