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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.ci {
  width: 100%;
  max-width: 320px;
  display: grid;
  gap: 16px;
}

.ci__field {
  display: block;
}

.ci__input {
  width: 100%;
  box-sizing: border-box;
  padding: 12px 16px;
  border-radius: 12px;
  border: 0;
  background: #fff7e6;
  color: #17141a;
  font-weight: 600;
  font-size: 18px;
  line-height: 1.3;
  font-family: "SFMono-Regular", Consolas, monospace;
  letter-spacing: 0.06em;
}
.ci__input:focus {
  outline: 2px solid #5b8cf8;
  outline-offset: 2px;
}

.ci__track {
  display: flex;
  align-items: center;
  gap: 4px;
}

.ci__seg {
  flex: 1;
  height: 4px;
  border-radius: 4px;
  background: rgba(255, 247, 230, 0.16);
  overflow: hidden;
}

.ci__segFill {
  display: block;
  width: 100%;
  height: 100%;
  border-radius: 4px;
  background: #5b8cf8;
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 220ms ease-out;
}

.ci__gap {
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: rgba(255, 247, 230, 0.16);
  transform: scale(0.4);
  opacity: 0;
  transition: transform 220ms cubic-bezier(0.34, 1.56, 0.64, 1), opacity 220ms ease-out, background-color 220ms ease-out;
}

.ci__gap--on {
  opacity: 1;
  transform: scale(1);
  background: #5b8cf8;
}

@media (max-width: 340px) {
  .ci__input {
    padding: 8px 12px;
    font-size: 16px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .ci__segFill, .ci__gap {
    transition: none;
  }
}