html {
  font-size: 10px;
  background: -webkit-linear-gradient(45deg, #fdc76a, #ef4d9e);
  background-color: #1d1f21;
  background-size: cover;
}
body,html {
  min-height: 100%;
  margin: 0;
  padding: 0;
  font-family: 'Source Sans Pro', sans-serif;
}

.container {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.masthead {
  align-items: center;
  justify-content: center;
  text-align: center;
  margin: 10rem 0 0;
}

h1 {
  text-align: center;
  font-size: 4rem;
  margin: 0;
  line-height: 3rem;
}

.masthead p {
  font-size: 2rem;
  color: rgba(0, 0, 0, 0.6);
}

.keys {
  display: flex;
  flex: 1;
  align-items: center;
  justify-content: center;
}

.key {
  border-radius: .5rem;
  margin: 1rem;
  font-size: 1.5rem;
  padding: 2.5rem .5rem;
  transition: all .07s ease;
  width: 10rem;
  text-align: center;
  color: white;
  background: rgba(255, 255, 255, 0.2);
}

.playing {
  transform: scale(1.1);
  border-color: #ffc600;
  box-shadow: 0 0 1rem #ffc600;
}

kbd {
  display: block;
  font-size: 4rem;
}

.sound {
  font-size: 1.4rem;
  text-transform: uppercase;
  letter-spacing: .1rem;
  color: rgba(0, 0, 0, 0.6);
}

.colophon {
  align-items: center;
  justify-content: center;
  text-align: center;
  margin: 4rem 0;
}

.colophon p {
  font-size: 1.6rem;
  color: rgba(0, 0, 0, 0.6);
}

.colophon a {
  align-self: flex-end;
  color: #212121;
  background: #ffc600;
  transition: all .2s ease;
}

.colophon a:hover {
  background: #fff;
}