.piano-container {
  overflow: auto;
}

.piano {
  box-sizing: border-box;
  overflow: auto;
  float: left;
  margin: 0;
  padding: 0;
}

.piano.small {
  font-size: 10px;
}

.piano-key {
  margin: 0;
  padding: 0;
  list-style: none;
  position: relative;
  float: left;
}

ul.piano .white {
  height: 16em;
  width: 4em;
  z-index: 1;
}

ul.piano .black {
  height: 8em;
  width: 2em;
  margin: 0 0 0 -1em;
  z-index: 2;
}

.piano-key.a,
.piano-key.g,
.piano-key.b,
.piano-key.d,
.piano-key.e {
  margin: 0 0 0 -1em;
}