.join-modal-overlay {
  display: none; /* 기본적으로 숨김 */
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.4); /* 반투명 배경 */
  justify-content: center;
  align-items: center;
  z-index: 2000;
}