@keyframes pulse {
  0% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.1);
  }
  100% {
    transform: scale(1);
  }
}
body {
  height: 100dvh;
  width: 100dvw;
  display: flex;
  align-items: center;
  justify-content: center;
}
.blue,
.red {
  border-radius: 50%;
  width: 36px;
  height: 36px;
  padding: 8px;

  color: #f0f0f0;
  text-align: center;

  font: 32px Arial, sans-serif;
}

.blue {
  background-color: blue;
  border: 2px solid darkblue;
}

.red {
  background-color: red;
  border: 2px solid darkred;
}

.balls {
  display: flex;
  flex-direction: row;
  gap: 2ch;
}

.loading {
  animation: pulse 2s infinite;
}

@media (max-width: 470px) {
  .balls {
    flex-direction: column;
    gap: 1ch;
  }
}