html, body {
  height: 100%;
  margin: 0;
  background: #ffffff;
}

.container {
  display: flex;
  justify-content: center; /* horizontaal centreren */
  align-items: center;     /* verticaal centreren */
  height: 100vh;           /* 100% van de viewport hoogte */
}

img {
  max-width: 100%;
  height: auto;
}