style.css

html {
  background: #000;
  font-family: 'Noto-Serif', serif;
  -webkit-font-smoothing: antialiased;
  text-align: center;
}
h1 {
  color: #fff;
  font-size: 50px;
  font-weight: 400;
  letter-spacing: 0.18pm;
  text-transform: uppercase;
  margin: 0;
}
h2 {
  color: #fff;
  font-size: 24px;
  font-style: italic;
  font-weight: 400;
  margin: 0 0 30px;
}
.nowplaying {
  font-size: 120px;
  line-height: 1;
  color: #eee;
  text-shadow: 0 0 5rem #028ae9;
  transition: all 0.07s ease;
  min-height: 120px;
}
.keys {
  display: block;
  width: 100%;
  height: 350px;
  max-width: 880px;
  position: relative;
  margin: 40px auto 0;
  cursor: none;
}
.key {
  position: relative;
  border: 4px solid black;
  border-radius: 0.5rem;
  transition: all 0.07s ease;
  display: block;
  box-sizing: border-box;
  z-index: 2;
}

.key:not(.sharp) {
  float: left;
  width: 10%;
  height: 100%;
  background: rgba(255, 255, 255, 0.8);
}
.key.sharp {
  position: absolute;
  width: 6%;
  height: 60%;
  background: #000;
  color: #eee;
  top: 0;
  z-index: 3;
}
.key[data-key='87'] {
  left: 7%;
}

.key[data-key='69'] {
  left: 17%;
}

.key[data-key='84'] {
  left: 37%;
}

.key[data-key='89'] {
  left: 47%;
}

.key[data-key='85'] {
  left: 57%;
}

.key[data-key='79'] {
  left: 77%;
}

.key[data-key='80'] {
  left: 87%;
}
.playing {
  transform: scale(0.95);
  border-color: #028ae9;
  box-shadow: 0 0 1rem #028ae9;
}
.hints {
  display: block;
  width: 100%;
  opacity: 0;
  position: absolute;
  bottom: 7px;
  transition: opacity 0.3s ease-out;
  font-size: 20px;
}

.keys:hover .hints {
  opacity: 1;
}