.floating-btn {
  position: fixed;
  right: 20px;
  bottom: 20px;
  width: 64px;
  height: 64px;
  background-color: rgba(128, 128, 128, 0.6);
  border-radius: 50%;
  border: none;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.25);
  touch-action: none;
  outline: none;
  -webkit-tap-highlight-color: transparent;

  /* アニメーションをなめらかに */
  transition:
    transform 0.08s ease,
    box-shadow 0.08s ease,
    background-color 0.1s ease;
}

.floating-btn.is-pressed {
  transform: scale(0.92);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
  background-color: rgba(128, 128, 128, 0.9);
}

.floating-btn img {
  width: 60%;
  height: 60%;
  object-fit: contain;
  pointer-events: none;
}