.cover-play-btn {
  position: absolute;
  top: calc(var(--u) * 4);
  left: calc(var(--u) * 4);
  width: calc(var(--u) * 12);
  height: calc(var(--u) * 12);
  padding: 0;
  border: 0;
  background: #2a7fff;
  border-radius: 50%;
  cursor: pointer;
  z-index: 30;
  filter: drop-shadow(0 4px 12px rgba(0,0,0,0.35));
  transform-origin: center;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform .15s ease;
}

.cover-play-btn:active {
  transform: scale(0.92);
}

/* Idle play triangle */
.np-play {
  width: 45%;
  height: 45%;
  display: block;
  margin-left: 6%; /* optical center for triangle */
}

/* Equalizer bars (shown while audio is playing) */
.np-eq {
  display: none;
  width: 50%;
  height: 50%;
  align-items: flex-end;
  justify-content: space-between;
}

.np-eq-bar {
  display: block;
  width: 22%;
  height: 100%;
  background: #fff;
  border-radius: calc(var(--u) * 0.3);
  transform-origin: bottom center;
  transform: scaleY(0.35);
}

.cover-play-btn.playing .np-play { display: none; }
.cover-play-btn.playing .np-eq   { display: flex; }

.cover-play-btn.playing .np-eq-bar:nth-child(1) { animation: np-eq-bounce 0.7s ease-in-out infinite;        }
.cover-play-btn.playing .np-eq-bar:nth-child(2) { animation: np-eq-bounce 0.5s ease-in-out 0.15s infinite; }
.cover-play-btn.playing .np-eq-bar:nth-child(3) { animation: np-eq-bounce 0.6s ease-in-out 0.30s infinite; }

@keyframes np-eq-bounce {
  0%, 100% { transform: scaleY(0.3); }
  50%      { transform: scaleY(1);   }
}