dialog{position:absolute;left:0;right:0;width:-moz-fit-content;width:fit-content;height:-moz-fit-content;height:fit-content;margin:auto;border:solid;padding:1em;background:#fff;color:#000;display:block}dialog:not([open]){display:none}dialog+.backdrop{background:rgba(0,0,0,.1)}._dialog_overlay,dialog+.backdrop{position:fixed;top:0;right:0;bottom:0;left:0}dialog.fixed{position:fixed;top:50%;transform:translateY(-50%)}