.nu_mask{position:absolute;top:0;left:0;width:100%;height:100%;background-color:rgba(0,0,0,.6);z-index:-1;box-sizing:border-box}
button.nu_mask{border:none 0;-webkit-appearance:none;border-radius:0;padding:0}
.nu_modal{position:fixed;top:0;left:0;width:100%;height:100%;display:block;visibility:hidden;border:none 0;padding:0;margin:0;box-sizing:border-box;background-color:transparent}
.nu_modal[open]{visibility:visible}
.nu_modal{opacity:0;transition:opacity .2s,visibility .2s}
.nu_modal[open]{opacity:1;transition:opacity .2s}