Use pandoc-generated source code highlighting CSS

I previously included hard-coded CSS.  Pandoc will apparently generate
what is needed for the page, but I didn't have that included in my
template.

I chose Tango out of a nearly 20y personal preference now, ever since I
used the Tango Icon Theme in Ubunutu Dapper Drake (6.06), my introducing
to GNOME/GTK.  I might have used Breezy, too, I don't recall.

Prior to that I think I used Mandrake (before it was Mandriva), which
was the first distro I tried, after my laptop's HDD died and I was
awaiting a replacement (couldn't run Windows without a HDD).

...anyway.

src/pandoc.tpl

@@ -22,6 +22,11 @@ $if(tags)$
 $endif$
 </article>
 
+<style>
+  /* pandoc-generated */
+  $highlighting-css$
+</style>
+
 $for(include-after)$
 
 $include-after$

src/post2html

@@ -136,6 +136,7 @@ main()
          --standalone --template src/pandoc.tpl \
          --metadata pagetitle:ignoreme \
          --wrap none \
+         --highlight-style tango \
          -B <( src/mkheader post @__PAGE_TITLE__@ ) \
          -A src/footer.tpl.htm \
          < <( prefmt < "$file" ) \

style.css

@@ -786,39 +786,6 @@ footer .site-nav > nav > ul > li a {
   }
 }
 
-/*** https://github.com/jgm/highlighting-kate/blob/master/css/hk-tango.css ***/
-/* GNU GPLv2 */
-/* Loosely based on pygment's tango colors */
-/* Modified where indicated by Mike Gerwitz */
-table.sourceCode, tr.sourceCode, td.sourceCode, table.sourceCode pre
-{ margin: 0; padding: 0; border: 0; vertical-align: baseline; border: none; background-color: #f8f8f8 }
-td.nums { text-align: right; padding-right: 5px; padding-left: 5px; background-color: #f0f0f0; }
-td.sourceCode { padding-left: 5px; }
-code.sourceCode { background-color: #f8f8f8; }
-pre.sourceCode {
-  /* modified by Mike Gerwitz */
-  padding: 1em;
-  margin: 0 -1em;
-
-  background-color: #f8f8f8;
-  line-height: 125%
-}
-td.nums pre { background-color: #f0f0f0; line-height: 125% }
-code.sourceCode span.kw { color: #204a87; font-weight: bold } /* Keyword */
-code.sourceCode span.dt { color: #204a87 } /* Keyword.Type */
-code.sourceCode span.dv { color: #0000cf } /* Literal.Number.Integer */
-code.sourceCode span.bn { color: #0000cf } /* Literal.Number.Hex */
-code.sourceCode span.fl { color: #0000cf } /* Literal.Number.Float */
-code.sourceCode span.ch { color: #4e9a06 } /* Literal.String.Char */
-code.sourceCode span.st { color: #4e9a06 } /* Literal.String */
-code.sourceCode span.co { color: #8f5902; font-style: italic } /* Comment */
-code.sourceCode span.ot { color: #8f5902 } /* Comment.Preproc */
-code.sourceCode span.al { color: #ef2929 } /* Generic.Error */
-code.sourceCode span.fu { color: #000000 } /* Name.Function */
-code.sourceCode span.re { }
-code.sourceCode span.er { color: #a40000; border: 1px solid #ef2929 } /* Error */
-
-
 /* Finally, the perpetual pain in my ass as a web developer: IE.  IE11 is
  * the only version I attempt here, enough to make it presentable and warn
  * the user. */