header {
  background-color:gray;
  padding: 30px;
  text-align: center;
  color:white;
}
footer {
  background-color:gray;
  padding: 30px;
  text-align: center;
  color:white;
}
#txt {
  float: center;
  width: 100%; 
}

#pic {
  float: center;
  background-image: url("https://projects.codecraftworks.com/web/oyvMCc7s423nxawkOOf4/assets/spaceship3.png");
  background-size: 1136px 405.50px;
}

.center {
  display: block;
  margin-left: auto;
  margin-right: auto;
  width: 50%;
}

h2 {color:black;}