* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}

html {
  /* height: 100vh; */
  background-image: url(background.jpg);
  background-position: center;
  background-size: cover;
  font-size: 62.5%;
}

body {
  font-family: sans-serif;
}

.keys {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.key {
  color: #fff;
  border: 0.4rem solid #000;
  width: 10rem;
  text-align: center;
  background: rgba(0, 0, 0, 0.4);
  text-shadow: 0 0 0.5rem black;
  border-radius: 1rem;
  margin: 1rem;
  padding: 1rem 0.5rem;
  transition: all 0.05s ease-in;
}

.sound {
  font-size: 1.4rem;
  text-transform: uppercase;
  letter-spacing: 0.1rem;
  color: #ffc600;
}

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

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