html {
  font-size: 10px;
  background: #aeb7b3;
}

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

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

.keys-row-1 {
  display: flex;
  flex: 1;
  align-items: center;
  justify-content: center;
}
.keys-row-2 {
  display: flex;
  flex: 1;
  align-items: center;
  justify-content: center;
}
.keys-row-3 {
  display: flex;
  flex: 1;
  align-items: center;
  justify-content: center;
}

.key {
  border: 0.4rem solid black;
  background: rgba(0, 0, 0, 0.37);
  border-radius: 0.3rem;
  margin: 2rem;
  padding: 1rem 0.5rem;
  width: 3rem;
  text-align: center;
  transition: 0.15s ease-in-out;
  text-shadow: 0 0 0.5rem grey;
}

.playing {
  transform: scale(1.2);
  border: 0.4rem solid #d0efb1;
  background: rgba(0, 0, 0, 0);
}

kbd {
  font-size: 4rem;
}