@media (max-width: 639px) {
  .assign-window {
    top: 0 !important;
    left: 0 !important;
    transform: none !important;
    width: 100vw !important;
    max-width: 100vw !important;
    height: 100dvh;
    max-height: 100dvh !important;
    border-radius: 0 !important;
  }
}