I need the h1 text to be in the middle of its background image vertically.
/* Header Container image */
.header {
  background-image: url("https://content.codecademy.com/courses/web-101/unit-6/htmlcss1-img_burgerphoto.jpeg");
  background-position: center;
  background-size: cover;
  height: 420px;
}
/* Header Itself */
.header h1 {
  background-color: rgba(5, 168, 170, 0.6);
  color: #FFF;
  max-width: 165px;
  margin: 0 auto;
}<div class="header">
  <h1>BBQ BACON BURGER</h1>
</div> 
    