.topnav {
  background-color: #333;
  overflow: hidden;
}

/* Style the links inside the navigation bar */
.topnav a {
  float: left;
  color:white;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-size: 17px;
}

/* Change the color of links on hover */
.topnav a:hover {
  background-color: gray;
  color: black;
}

/* Add a color to the active/current link */
.topnav a.active {
  background-color: black;
  color: white;
}

body{
  background-image: url(bh.jpg);
  background-size: 100vw auto;
  color: white;
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.2;
  min-height: auto;
  min-width: auto;
  background-attachment: fixed;
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
}

a{
  color: white;
}

.hubblelaw{
  float: left;
  font-size: 6vh;
  margin: 20vh 8vw;
}

.hubblelawimg{
  float:right;
  margin: 6vh 6vw;
  height: 40vh;
  width: auto;
}

.friedmann{
  float: left;
  font-size: 6vh;
  margin: 20vh 4vw;
}

.friedmannimg{
  float: right;
  margin: 10vh 3vw;
  height: 30vh;
  width: auto;
}


.fateofuniverse{
  float: left;
  font-size: 6vh;
  margin: 30vh 4vw;
}

.expansionuniverseimg{
  float: right;
  margin: 6vh 6vw;
  height: 40vh;
  width: auto;
}