header {
  text-align: center;
}

img.pic {
  width: 540px; /* you can use % */
  height: auto;
}

@font-face {
  font-family: myFirstFont;
  src: url(DTM-Sans.otf);
}

* {
  font-family: myFirstFont;
  background-color: black;
  color: white;
}

.nav-bar {
  border: 5px white;
  display: flex;
  margin: auto;
}

.pro {
  border: 5px white;
}

.nav-bar-link {
  padding: 20px;
  margin: auto;
}