.main-div {padding-left: 20px;}
p, ul, ol, li,  h1, h2, h3   {margin-left:auto; margin-right:auto}
  p, l1, ul, ol {max-width: 30em; }
  h1 {max-width: 11em; }
  h2 {max-width: 14em; }
  h3 {max-width: 17em; }