.ooo{
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  overflow-y: scroll;
}

*[ooo-appear]{
  position: fixed;
  top: 0;
}

*[ooo-position='left']{
  left: max(8vw, calc(50vw - 506px));
}

*[ooo-position='center']{
  left: 50%;
  /* transform: translateX given by JS */
}

*[ooo-position='right']{
  right: max(8vw, calc(50vw - 506px));;
}

.ooo-dummy{
  width: 100%;
}