.outer-wrap {
  width: 100%;
  height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background: #00bcd4;
}
.title {
  color: #fff;
  font-size: 1.4em;
  font-weight: 300;
}
.title-accent {
  border-bottom: 1px solid #fffde7;
}

.inner-wrap {
  display: flex;
  flex-direction: column;
  padding: 1em;
  background: darken( #ccc, 10% );
}

.button {
  position: relative;
  overflow: hidden; // so important!
  margin: 0.5em 0;
  width: 250px;
  height: 75px;
  
  color: rgba(0, 0, 0, 0.56);
  font-size: 1.1em;
  font-weight: 500;
  background: #ccc;
  border-radius: 0.25em;
  text-align: center;
  line-height: 75px;
  -webkit-tap-highlight-color: transparent;
}

.button-ink {
  box-shadow: 0 2px 4px rgba(#000, 0.4);
  
  &.raised {
    animation: raised 0.45s ease;
  }
}

.ink {
  position: absolute;
  display: block;
  
  transform: scale(0);
  border-radius: 51%;
  background: #ffeb3b;
  
  &.spill {
    animation: spill 0.65s ease;
  }
}

@keyframes spill {
  100% {
    opacity: 0;
    transform: scale(3.5);
  }
}
@keyframes raised {
  100% {
    box-shadow: 0 4px 8px rgba(#000, 0.4);
  }
}



/* resets */
html {
  font: 1em/1.4em sans-serif;
  -webkit-font-smoothing: antialiased;
}
a {
  text-decoration: none;
}