[plt-scheme] A suggestion for Scribble CSS

As currently rendered headings in Scribble are equidistant to the
paragraph above and the paragraph below.  Increasing the distance
above a heading makes the structure of the document more apparent.  I
have found the following snippet of CSS improves the appearance of
Scribble pages in all reasonable web browsers (unreasonable browsers
have not been tested):


   h1, h2, h3, h4, h5, h6, h7, h8 {
     margin-top: 1.75em;
     margin-bottom: 0.5em;
   }

N.