body {
  background-image: url("https://i.ibb.co/f8VJRRc/hearts-and-stars.gif");
  color: black;
  font-family: Verdana;
  width:900px;
  height:auto;
  outline-color:blue;
}

container {
  width: 900px; /* adjust to container size as needed */
  height: auto; /* adjust to container size as needed */
  outline-color: pink;
  outline-width: 4px;
}

container img {
  max-width: 100%;
  max-height: 100%;
  display: block;
}