@theoryofnekomata/piano-keyboard/build/piano-keyboard.css

Simple piano keyboard in JavaScript

.piano-keyboard {
  position: relative;
  color: inherit;
  background-color: inherit;
  min-height: 16px;
  border-right: 0.5px solid currentColor;
  box-sizing: border-box;
}

.piano-keyboard > .key {
  border: 0.5px solid currentColor;
  padding: 0;
  margin: 0;
  position: absolute;
  top: 0;
  color: inherit;
  cursor: pointer;
  box-sizing: border-box;
}

.piano-keyboard > .key:focus {
  outline: none;
}

.piano-keyboard > .white.key {
  background-color: transparent;
  height: 100%;
  border-right: none;
}

.piano-keyboard > .black.key {
  background-color: currentColor;
  height: 61.8133989%;
  z-index: 1;
}

.piano-keyboard > .key.-active {
  background-color: Highlight;
}

.piano-keyboard > .key::after {
  font-size: 50%;
  display: block;
  position: absolute;
  bottom: 0;
  width: 100%;
  text-align: center;
}

.piano-keyboard > .black.key::after {
  font-size: 12.5%;
  transform: rotate(-90deg);
  color: #fff;
  bottom: auto;
}

.piano-keyboard > .black.key.-active::after {
  color: inherit;
}