body {
  margin: 0;
  padding: 0;
}
#wrap {
  height: 5000px;
}
.jumbotron {
  margin-bottom: 0;
  text-align: center;
}
.navbar.fixed {
  position: fixed;
  top: 0;
  width: 100%;
}
.block {
  font-size: 26px;
}
.block.fixed {
  color: red;
}
.block--navbar {
  line-height: 48px;
}