Added/Cleanup coloured css elements

dav_base/templates/dav_base/css_demo.html

@@ -81,6 +81,7 @@
 <p class="text-blue"><span class="label label-blue">text-blue</span> {% lorem %}</p>
 <p class="text-yellow"><span class="label label-yellow">text-yellow</span> {% lorem %}</p>
 <p class="text-red"><span class="label label-red">text-red</span> {% lorem %}</p>
+<p class="text-black"><span class="label label-black">text-black</span> {% lorem %}</p>
 <p class="text-mandarin"><span class="label label-mandarin">text-mandarin</span> {% lorem %}</p>
 <p class="text-lime"><span class="label label-lime">text-lime</span> {% lorem %}</p>
 <p class="text-cyan"><span class="label label-cyan">text-cyan</span> {% lorem %}</p>