But this looks just as readable to me, and declaring font in pre would work correctly

p, pre, ul, ol {
font-size:13px;
color: #000000;
font-family: Arial, Helv, Helvetica, Geneva, sans-serif;
}

p {
margin:0px 10px 5px 10px;

}

pre {
margin:0px 10px 10px 10px;
font-family: Courier, “Courier New”, monospace;
}