body { 
    margin-left: 10%; 
    margin-right: 10%; 
    font-family: sans-serif;
        }
   h1 { margin-left: -6% }
   h2 { margin-left: -5% }
   h3 { margin-left: -4% }
   h4 { margin-left: -3% }
   h5 { margin-left: -2% }
   h6 { margin-left: -1% }
   pre {
     font-weight: bold;
     white-space: pre; font-family: monospace;
     margin-left: 05%; 
       }
   em { font-style: italic; font-weight: bold }
   strong { font-weight: bold }
   .navbar {text-align: center }