chamilo-lms2/main/inc/lib/javascript/chosen/bootstrap-chosen.css

 .chosen-container-multi .chosen-choices {
     border-radius: 4px !important;
     padding: 3px 11px !important;
 }

 .chosen-container-multi .chosen-choices li.search-field input[type="text"] {
    height:auto;
    padding:5px 0 !important;

    color: #333 !important;
    font-family: inherit !important;
    font-size: 14px !important;
        border-radius: 4px !important;

}
 .chosen-container-multi.chosen-container-active .chosen-choices,
.chosen-container.chosen-container-single.chosen-container-active .chosen-single,
.chosen-container .chosen-search input[type=text]:focus{
    border-color: #66AFE9;
    outline: 0;
    -webkit-box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075),0 0 8px rgba(102, 175, 233, 0.6);
    box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075),0 0 8px rgba(102, 175, 233, 0.6);

     border-radius: 4px !important;
}

 .chosen-container-multi .chosen-results li.result-selected{
    display: list-item;
    color: #ccc;
    cursor: default;
    background-color: white;
}