html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffd23f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.link {
  position: relative;
  display: inline-block;
  padding: 8px 4px;
  color: #17141a;
  text-decoration: none;
  font-weight: 800;
  font-size: clamp(18px, 5vw, 26px);
  line-height: 1.2;
}
.link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 3px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: center;
  transition: transform 300ms cubic-bezier(0.2, 1.4, 0.4, 1);
}
.link:hover::after, .link:focus-visible::after {
  transform: scaleX(1);
}
.link.is-demo::after {
  animation: underline-center 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

@keyframes underline-center {
  0%, 100% {
    transform: scaleX(0);
  }
  35%, 60% {
    transform: scaleX(1);
  }
}
@media (prefers-reduced-motion: reduce) {
  .link::after, .link.is-demo::after {
    transition: none;
    animation: none;
  }
  .link:hover::after, .link:focus-visible::after {
    transform: scaleX(1);
  }
}