/* mosaic-reset: uiverse 컴포넌트 공통 전제 (box-sizing + 기본 sans-serif) */
*, *::before, *::after { box-sizing: border-box; }
:where(body) { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; }

/* 단독 동작용 무대 — 어두운 회색 dot이 보이도록 밝은 배경 + 중앙 정렬 */
html, body { margin: 0; height: 100%; }
body {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background: #e8e8e8;
}

/* ---- 컴포넌트 본체 (uiverse: jolly-kangaroo-36) ---- */
.newtons-cradle {
  --uib-size: 50px;
  --uib-speed: 1.2s;
  --uib-color: #474554;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: var(--uib-size);
  height: var(--uib-size);
}

.newtons-cradle__dot {
  position: relative;
  display: flex;
  align-items: center;
  height: 100%;
  width: 25%;
  transform-origin: center top;
}

.newtons-cradle__dot::after {
  content: '';
  display: block;
  width: 100%;
  height: 25%;
  border-radius: 50%;
  background-color: var(--uib-color);
}

.newtons-cradle__dot:first-child {
  animation: swing var(--uib-speed) linear infinite;
}

.newtons-cradle__dot:last-child {
  animation: swing2 var(--uib-speed) linear infinite;
}

@keyframes swing {
  0% {
    transform: rotate(0deg);
    animation-timing-function: ease-out;
  }

  25% {
    transform: rotate(70deg);
    animation-timing-function: ease-in;
  }

  50% {
    transform: rotate(0deg);
    animation-timing-function: linear;
  }
}

@keyframes swing2 {
  0% {
    transform: rotate(0deg);
    animation-timing-function: linear;
  }

  50% {
    transform: rotate(0deg);
    animation-timing-function: ease-out;
  }

  75% {
    transform: rotate(-70deg);
    animation-timing-function: ease-in;
  }
}