html {
  font-size: 24px;
  background: linear-gradient(#193549e5 40%, #ffc80077), url('./background.jpg') no-repeat top center;
  height: 100vh;
}

body, html {
  margin: 0;
  padding: 0;
  font-family: sans-serif;
}

.keys {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  margin-top: 40vh;
}

.key {
  width: 2rem;
  height: 2rem;
  display: flex;
  flex-direction: column;
  border-radius: 50%;
  border: 2px solid #000;
  padding: .5rem;
  margin: .5rem;
  text-align: center;
  color: #FFF;
  background: rgba(43, 43, 43, 0.5);
  transition: all .07s ease;
}

.key:hover {
  cursor: pointer;
}

.sound {
  text-transform: uppercase;
  font-size: 0.4rem;
  color: #ffc600;
}

.playing {
  transform: scale(1.1);
  border-color: #ffc600;
  box-shadow: 0 0 0.2rem #ffc600;
}