CSS of page contents with two levels

[shawna-slh]

spacing of nest list items bugs me! I think best to use the less spacing between secondary list items.

[shawna-slh]

For https://github.com/w3c/wai-presentations2all/pull/86/files I did:

  ul li {
    margin-top: 5px !important;
    margin-bottom: 0px !important;
  }