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);
}

.kfs {
  position: relative;
  display: inline-flex;
  max-width: 100%;
}

.kfs__group {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  max-width: 100%;
}

.kfs__btn {
  position: relative;
  z-index: 1;
  appearance: none;
  border: none;
  border-radius: 8px;
  background: transparent;
  color: #fff7e6;
  font-size: 12px;
  font-weight: 600;
  padding: 8px 12px;
  cursor: pointer;
  white-space: nowrap;
  flex: 0 0 auto;
}
.kfs__btn:focus-visible {
  outline: 2px solid #2f6df6;
  outline-offset: 2px;
}
.kfs__btn[aria-checked=true] {
  color: #17141a;
}

.kfs__ring {
  position: absolute;
  top: 0;
  left: 0;
  z-index: 0;
  border-radius: 8px;
  background: #5b8cf8;
  will-change: transform, width, height;
}

@media (max-width: 340px) {
  .kfs__btn {
    font-size: 11px;
    padding: 4px 8px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .kfs__ring {
    transition: none;
  }
}