body    {
    margin: 0;
    padding: 0;
}

.jumbotron {
  background-color: #D3D3D3;
  padding: 50px;
}

.row-centered {
    text-align: center;
}

.col-centered {
    display: inline-block;
    float: none;
    text-align: left;
    margin-right: -4px;
}

.navbar {
  margin-bottom: 0;
  border: none;
  border-radius: 0;
  background-color: lightblue;
}

ul button {
  margin: 5px;
}
                    
footer p {
  background-color: #fff;
  padding: 5px;
  margin: 0;
}