A modified version of a HN Dark Theme that works with refined-hacker-news

HNDark.css

/* Placeholder: /*[[upvotecolor]]*/
/* Replace with #6F6F6F for gray upvote arrow. */
/* Replace with #FF6600 for orange upvote arrow. */

@namespace url(http://www.w3.org/1999/xhtml);
@-moz-document domain("news.ycombinator.com") {
  /* main body styles */
  body {
    background-color: #262626;
  }
  body>center>table,
  input,
  textarea {
    background-color: #222;
  }
  pre,
  code {
    /* The important flags makes sure that this works with the Refined HN extension */
    background-color: #333333 !important;
    display: block;
  }
  body>center>table>tbody>tr:first-child>td {
    background-color: #ff6600;
  }
  /* bright text on most pages */
  .title a:link,
  span.comment font,
  span.comment font a:link,
  label,
  u a:link,
  .yclinks a:link,
  body:not([id]),
  td:nth-child(2):not(.subtext)>a:link,
  input,
  textarea,
  p>a,
  a>u,
  .c00,
  .c00 a:link,
  a[href="http://www.ycombinator.com/apply/"],
  form {
    color: #ccc !important;
  }
  .__rhn__options-bar a {
    color: #ccc !important;
  }
  .admin td {
    color: #aaa;
  }
  /* search box and comment box */
  input,
  textarea {
    border: 1px solid #828282;
  }
  /* upvote arrow */
  .votearrow {
    width: 0;
    height: 0;
    border-left: 4px solid transparent;
    border-right: 4px solid transparent;
    border-bottom: 8px solid #6F6F6F;
    background: none;
    margin: 6px 2px 4px;
  }
}

This is based on https://userstyles.org/styles/184485/hacker-news-basic-dark
and supports: https://github.com/plibither8/refined-hacker-news