Big up for the new cool new skin on mojoPortal!

I´m having problems making list-style:none; on my unordered list.

I found in the style.css of my skin where the bullets come from, but I can not override it!

.art-blockcontent-body ul li
{
  line-height: 125%;   
  color: #121212;
  padding: 0 0 0 16px;
  background-image: url('images/blockcontentbullets.png');
  background-repeat: no-repeat;
}/* end Box, BlockContent */

.art-post ul>li
{
  background-image: url('images/postbullets.png');
  background-repeat: no-repeat;
  padding-left: 16px;
  /* makes "ul li" not to align behind the image if they are in the same line */
  overflow-x: visible;
  overflow-y: hidden;
}

I have tried every scenarios... ".mylist ul li {list-style:none;} , ul.mylist li {list-style:none;}". Nothing seems to work. 

Hope you can help. Thanks