title: H1-H6 font sizes in HTML
body: <p>In HTML (and in typography in general, I suppose), there appears to be some defined sizes for H1-H6 -elements.</p>
  
  <p>Ie., if the baseline font size is 16px (or 100%), then h1 (w/c)ould be 2.25em (36px).
  And H2 (w/c)ould be 1.5em (24px). Et cetera.
  Where do these variables come from? The H1=36px, H2=24px, H3=21px, H4=18px, H5=16px, H6=14px, that is. (or, if you like, H1=2em, H2=1.5em, H3=1.17em, etc., the point isn't the numbers themselves, but the relation between them)</p>
  
  <p>Is there some mathematical formula for them? Does it have something to do with golden ratio or fibonacci? I haven't been able to find information on this.</p>
  
  <p>EDIT: to be more specific, what is the pattern; why does it go from 36 to 24 to 21, or start from 36 to begin with (or, if you like, from 2em to 1.5em to 1.17em, etc.)?</p>
  
  <p>Oh, I forgot to specify where I came up with the original numbers, they're from <a href="http://webtypography.net/Harmony_and_Counterpoint/Size/3.1.1/" rel="noreferrer">here</a></p>