Fix CSS syntax error in block-level vertical rhythm rule

The CSS rule that adds margins to block level elements is missing a comma. Edit your html-reset.css and look for this rule:

h1, h2, h3, h4, h5, h6
p, blockquote, pre,
ul, ol, dl,
hr, table, fieldset {
  margin: 1.5em 0;
}

And add a comma after the first line, so it looks this:

h1, h2, h3, h4, h5, h6,
p, blockquote, pre,
ul, ol, dl,
hr, table, fieldset {
  margin: 1.5em 0;
}