dialog {
  color: white;
  display: flex;
  flex-wrap: wrap;
  position: relative;
  justify-content: center;
  align-items: center;
  width: 250px;
  height: 200px;
  background: linear-gradient(to left, rgba(160, 0, 255, 0.8), black 50%, rgba(0, 0, 255, 0.8) 100%);
}
dialog button {
  position: relative;
  width: 150px;
}