jquery.mentionsInput.css

.mentions-wrapper textarea {
  width: 100%;
  display: block;
  padding: 9px;
  border-radius:3px;
  background: #fff;
  position: relative;
  outline: 0;
  overflow: auto;
  height: 100px;
  width: 500px;
  resize: none;
}

.mentions-wrapper .mentions-autocomplete-list {
  display: none;
  background: #fff;
  border: 1px solid #b2b2b2;
  position: absolute;
  z-index: 10000;

  -webkit-box-shadow: 0 2px 5px rgba(0, 0, 0, 0.148438);
     -moz-box-shadow: 0 2px 5px rgba(0, 0, 0, 0.148438);
          box-shadow: 0 2px 5px rgba(0, 0, 0, 0.148438);
}

.mentions-wrapper .mentions-autocomplete-list ul {
    margin: 0;
    padding: 0;
}

.mentions-wrapper .mentions-autocomplete-list li {
  background-color: #fff;
  padding: 0 5px;
  margin: 0;
  width: auto;
  border-bottom: 1px solid #eee;
  height: 26px;
  line-height: 26px;
  overflow: hidden;
  cursor: pointer;
  list-style: none;
  white-space: nowrap;
}

.mentions-wrapper .mentions-autocomplete-list li em {
  font-weight: bold;
  font-style: none;
}

.mentions-wrapper .mentions-autocomplete-list li:hover,
.mentions-wrapper .mentions-autocomplete-list li.active {
  background-color: #f2f2f2;
}

.mentions-wrapper .mentions-autocomplete-list li b {
  background: #ffff99;
  font-weight: normal;
}

.mentions-wrapper .mentions {
  white-space: pre-wrap;
  word-wrap: break-word;
}

.mentions-wrapper .mentions > div {
  color: transparent;
  white-space: pre-wrap;
  width: 100%;
}

.mentions-wrapper .mentions > strong {
  font-weight:normal;
  background: #d8dfea;
}

.selected {
  background-color: #eee !important;
}