jquery.ui.autocomplete.css

ul.jq-ui-autocomplete {
    position: absolute;
    overflow: hidden;
    background-color: #fff;
    border: 1px solid #aaa;
    margin: 0px;
    padding: 0;
    list-style: none;
    font: normal .75em/.75em Verdana, Arial, sans-serif;
    color: #333;
}
ul.jq-ui-autocomplete li { 
  display: block; 
  padding: .3em .5em .3em .3em; 
  overflow: hidden;
  width: 100%;
}

ul.jq-ui-autocomplete li.active { 
  background-color: #3875d7; 
  color: #fff;
}