dialog {
   position: absolute;
   left: 0; right: 0;
   width: -moz-fit-content;
   width: -webkit-fit-content;
   width: fit-content;
   height: -moz-fit-content;
   height: -webkit-fit-content;
   height: fit-content;
   margin: auto;
   border: solid;
   padding: 1em;
   background: white;
   color: black;
   display: block;
}

dialog:not([open]) {
   display: none;
}

dialog + .backdrop {
   position: fixed;
   top: 0; right: 0; bottom: 0; left: 0;
   background: rgba(0,0,0,0.1);
}

._dialog_overlay {
   position: fixed;
   top: 0; right: 0; bottom: 0; left: 0;
}

dialog.fixed {
   position: fixed;
   top: 50%;
   transform: translate(0, -50%);
}