.ksrm-room-disabled{opacity:0.6; pointer-events:none; position:relative;}
.ksrm-room-disabled::after{
  content: attr(data-ksrm-msg);
  position:absolute; left:8px; right:8px; top:50%; transform:translateY(-50%);
  font-size:12px; color:#444; background:#fff; padding:4px 6px; border:1px dashed #ccc; border-radius:6px; text-align:center;
}