Wikipedia:Article templates/Ambox-project/colors.css

table.ambox td.ambox-shortcut {     /* The shortcut cell */
  width: 52px; 
  padding: 2px 0.5em 2px 0px;         /* 0px left, 0.5em right */
  text-align: center; 
}

table.ambox-policy {
  border-left: 10px solid #148C14;       /* Green */
/* border-right: 10px solid #148C14; */  /* If you want two green bars */
}

table.ambox-guideline {
  border-left: 10px solid #14678C;       /* Dark-blue */
}

table.ambox-history {
  border-left: 10px solid #CC0000;       /* Dark-Red */
}

table.ambox-disputed {
  border-left: 10px solid #CC0000;       /* Dark-Red */
}

table.ambox-proposal {
  border-left: 10px solid #9900CC;       /* Purple */
}

table.ambox-essay {
  border-left: 10px solid #FFCC33;       /* Yellow */
}