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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #fbf6ee;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.fo {
  box-sizing: border-box;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  width: clamp(288px, 92vw, 432px);
  padding-top: 16px;
  border-top: 2px solid #1b1a20;
}

.fo__mark {
  position: relative;
  flex: 0 0 auto;
  color: #1b1a20;
  font-weight: 800;
  font-size: 20px;
  line-height: 1.1;
  letter-spacing: -0.01em;
  text-decoration: none;
}

.fo__mark:focus-visible {
  outline: 2px solid #479089;
  outline-offset: 4px;
  border-radius: 4px;
}

.fo__line {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -4px;
  height: 3px;
  border-radius: 999px;
  background: #479089;
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 300ms cubic-bezier(0.2, 1.4, 0.4, 1);
}

.fo__mark:hover .fo__line,
.fo__mark:focus-visible .fo__line {
  transform: scaleX(1);
}

.fo__copy {
  flex: 0 1 auto;
  margin: 0;
  color: #575162;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.2;
}

.fo__social {
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  gap: 8px;
}

.fo__dot {
  --on: #ff4d1f;
  --on-ink: #1b1a20;
  display: grid;
  place-items: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: #ffffff;
  color: #575162;
  transition: transform 220ms cubic-bezier(0.2, 1.4, 0.4, 1), background-color 220ms ease-out, color 220ms ease-out;
}

.fo__dot--b {
  --on: #1b1a20;
  --on-ink: #ffffff;
}

.fo__dot--c {
  --on: #479089;
  --on-ink: #ffffff;
}

.fo__dot:hover,
.fo__dot:focus-visible {
  transform: translateY(-6px);
  background: var(--on);
  color: var(--on-ink);
}

.fo__dot:focus-visible {
  outline: 2px solid #1b1a20;
  outline-offset: 2px;
}

.fo.is-demo .fo__dot {
  animation-name: foLift;
  animation-duration: 2s;
  animation-timing-function: cubic-bezier(0.2, 1.4, 0.4, 1);
  animation-iteration-count: infinite;
  animation-fill-mode: backwards;
  transition: none;
}

.fo.is-demo .fo__dot--b {
  animation-delay: -0.6667s;
}

.fo.is-demo .fo__dot--c {
  animation-delay: -1.3333s;
}

.fo.is-demo .fo__line {
  animation-name: foLine;
  animation-duration: 2s;
  animation-timing-function: cubic-bezier(0.2, 0.8, 0.2, 1);
  animation-iteration-count: infinite;
  transition: none;
}

@keyframes foLift {
  0% {
    transform: translateY(0);
    background: #ffffff;
    color: #575162;
  }
  8%, 26% {
    transform: translateY(-6px);
    background: var(--on);
    color: var(--on-ink);
  }
  33.33%, 100% {
    transform: translateY(0);
    background: #ffffff;
    color: #575162;
  }
}
@keyframes foLine {
  0% {
    transform: scaleX(0);
  }
  45%, 78% {
    transform: scaleX(1);
  }
  88%, 100% {
    transform: scaleX(0);
  }
}
@media (max-width: 340px), (max-height: 220px) {
  .fo {
    gap: 8px;
    width: 100%;
    padding-top: 8px;
  }
  .fo__mark {
    font-size: 14px;
  }
  .fo__line {
    bottom: -3px;
    height: 2px;
  }
  .fo__copy {
    font-size: 10px;
  }
  .fo__social {
    gap: 4px;
  }
  .fo__dot {
    width: 22px;
    height: 22px;
  }
  .fo__dot svg {
    width: 13px;
    height: 13px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .fo__dot, .fo__line {
    animation: none !important;
    transition: none !important;
  }
}