.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;
  }

.hubble{
  display: flex;           /* Use flexbox for centering */
  justify-content: center; /* Center horizontally */
  align-items: center;     /* Center vertically (optional) */
  text-align: center;      /* Center text within the div */
  font-size: 50px;
  color: white;
}

.doppler{
  display: flex;           /* Use flexbox for centering */
  justify-content: center; /* Center horizontally */
  align-items: center;     /* Center vertically (optional) */
  text-align: center;      /* Center text within the div */
  font-size: 50px;
  color: white;
}

.redshift{
  display: flex;           /* Use flexbox for centering */
  justify-content: center; /* Center horizontally */
  align-items: center;     /* Center vertically (optional) */
  text-align: center;      /* Center text within the div */
  font-size: 50px;
  color: white;
}


.reldoppler{
  display: flex;           /* Use flexbox for centering */
  justify-content: center; /* Center horizontally */
  align-items: center;     /* Center vertically (optional) */
  text-align: center;      /* Center text within the div */
  font-size: 50px;
  color: white;
}

body{
  background-image: url(m101.jpg);
  background-size: 100vh auto;
  color: white;
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.2;
  min-height: 100vh;
  min-width: auto;
  background-attachment: fixed;
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
}

a{
  color: white;
}

.velocity-redshift{
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 40vh;
  width: auto;
}

.velocity-redshift:hover{
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 57vh;
  width: auto;
}