img { display: block; padding: 1em; margin-left: auto; margin-right: auto;}
p { margin: 1.5em; }
h1 { text-align: center; }
tt { color: #c01860; }
code { color: #18a030; }
h1, h2, dt { font-family: sans-serif; font-weight: bold; }
pre { border: solid gray 1px; margin: 2.5em; padding: 1em; }
li.subhead { margin-top: 0.6em; font-weight: bold; }
li.subhead ul { margin-top: 0; font-weight: normal; }