body, html {
    height: 100%;
}



/* Dropdown container - needed to position the dropdown content */
.dropdown {
  float: left;
  overflow: hidden;
}


/* When the screen is less than 600 pixels wide, hide all links, except for the first one ("Home"). Show the link that contains should open and close the topnav (.icon) */
@media screen and (max-width: 600px) {
  .topnav a:not(:first-child) {display: none;}
  .topnav a.icon {
    float: right;
    display: block;
  }
}

/* The "responsive" class is added to the topnav with JavaScript when the user clicks on the icon. This class makes the topnav look good on small screens (display the links vertically instead of horizontally) */
@media screen and (max-width: 600px) {
  .topnav.responsive {position: relative;}
  .topnav.responsive a.icon {
    position: absolute;
    right: 0;
    top: 0;
  }
  .topnav.responsive a {
    float: none;
    display: block;
    text-align: left;
  }
}

  .topnav.responsive .dropdown {float: none;}
  .topnav.responsive .dropdown-content {position: relative;}
  .topnav.responsive .dropdown .dropbtn {
    display: block;
    width: 100%;
    text-align: left;
  }

.footer {
   position: block;
   left: 0;
   bottom: 0;
   width: 100%;
   background-color: #4e5c70;
   color: white;
   text-align: center;
   margin-top: 20px;
   height: 50px;
}



/* Turn off parallax scrolling for tablets and phones. Increase the pixels if needed */
@media only screen and (max-device-width: 1366px) {
  .parallax {
    background-attachment: scroll;
  }
}

<!-- Background video-->

header video {
  position: absolute;
  top: 50%;
  left: 50%;
  min-width: 100%;
  width: auto;
  z-index: 0;

}

/* Place text in the middle of the image */
.hero-text {
	font-family: helvetica;
  text-align: center;
  position: absolute;
  top: 40%;
  left: 50%;
  transform: translate(-50%, -50%);
  color: white;
}
/* Star Images */
.col {
  position: relative;
  width: 100%;
}

.image {
  display: inline-block;
  width: 100%;
  height: auto;
}

.overlay {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  height: 100%;
  width: 100%;
  opacity: 0;
  transition: .5s ease;
  background-color: #222222;
  display: block;
}

.col-md-4:hover .overlay {
  opacity: 1;
}

.text {
  color: white;
  font-size: 20px;
  position: absolute;
  top: 50%;
  left: 50%;
  -webkit-transform: translate(-50%, -50%);
  -ms-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
  text-align: center;
  font-family: futura;
}