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);
}

.bg {
  position: relative;
  display: flex;
  border-radius: 12px;
  overflow: visible;
}

.bg__btn {
  position: relative;
  appearance: none;
  border: 1.5px solid rgba(255, 247, 230, 0.38);
  background: rgba(255, 247, 230, 0.06);
  color: #fff7e6;
  font-size: 13px;
  font-weight: 600;
  padding: 8px 16px;
  cursor: pointer;
  overflow: hidden;
  transition: background-color 220ms ease-out, color 220ms ease-out, border-color 220ms ease-out;
}
.bg__btn + .bg__btn {
  margin-left: -1.5px;
}
.bg__btn:first-child {
  border-radius: 12px 0 0 12px;
}
.bg__btn:last-child {
  border-radius: 0 12px 12px 0;
}
.bg__btn:hover, .bg__btn:focus-visible {
  z-index: 1;
}
.bg__btn:focus-visible {
  outline: 2px solid #5b8cf8;
  outline-offset: 2px;
}

.bg__btn--on {
  background: #0a4fe8;
  border-color: #0a4fe8;
  color: #fff7e6;
  z-index: 2;
}

.bg__ripple {
  position: absolute;
  border-radius: 50%;
  background: rgba(255, 247, 230, 0.5);
  pointer-events: none;
  will-change: width, height, opacity, clip-path;
}

.bg__seam {
  position: absolute;
  top: 4px;
  bottom: 4px;
  width: 1px;
  left: var(--seam-x, 0);
  transform: translateX(-50%);
  background: rgba(255, 247, 230, 0.16);
  pointer-events: none;
  z-index: 3;
}

@media (max-width: 340px) {
  .bg__btn {
    font-size: 12px;
    padding: 8px 12px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .bg__btn {
    transition: none;
  }
  .bg__ripple {
    display: none;
  }
}