body, html {
  height: 100%;
  margin: 0;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  overflow: hidden;
}

#chat-container {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: none;
}

.modal-content {
  text-align: center;
}