.seismo-rig > div {
  display: grid;
  width: min(220px, 100%);
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 7px;
  align-items: end;
  min-height: 120px;
}

.seismo-rig span {
  display: block;
  height: var(--quake, 20%);
  min-height: 16px;
  border-radius: 999px 999px 0 0;
  background: linear-gradient(180deg, var(--amber), var(--danger));
  animation: seismo-twitch 800ms steps(2, end) infinite;
}

.seismo-rig span:nth-child(even) {
  animation-delay: 140ms;
}

@keyframes seismo-twitch {
  50% { transform: translateY(-5px); }
}