How to modify jquery-token-input css to add a tiny rectangle around the X to cancel?

问题

I am using the jQuery tokenInput plugin. My current tokens look like this:

If you look at the token fields, the latest tag called mstagtesting has an X at the end, which appears on mouse hover.

I want to change the area around the X and introduce a rectangle around the X to make it look like these if hovered on :

How do I modify the css to add the rectangle of white background color around the X that serves to de-select a token when clicked on ? Thanks so much for your help and here is my css file:

/* Example tokeninput style #2: Mac Style */
fieldset.token-input-mac {
  position: relative;
  padding: 0;
  margin: 5px 0;
  background: #fff;
  width: 400px;
  border: 1px solid #A4BDEC;
  border-radius: 10px;
  -moz-border-radius: 10px;
  -webkit-border-radius: 10px;
}

fieldset.token-input-mac.token-input-dropdown-mac {
  border-radius: 10px 10px 0 0;
  -moz-border-radius: 10px 10px 0 0;
  -webkit-border-radius: 10px 10px 0 0;
  box-shadow: 0 5px 20px 0 rgba(0,0,0,0.25);
  -moz-box-shadow: 0 5px 20px 0 rgba(0,0,0,0.25);
  -webkit-box-shadow: 0 5px 20px 0 rgba(0,0,0,0.25);
}

ul.token-input-list-mac {
    position: relative;
    overflow: hidden;
    height: auto !important;
    cursor: text;
    font-size: 12px;
    min-height: 1px;
    z-index: 999;
    margin: 0;
    padding: 0;
    background: transparent;
}

ul.token-input-list-mac.error {
  border: 1px solid #C52020;
}

ul.token-input-list-mac li {
list-style-type: none;
}

li.token-input-token-mac p {
    display: inline;
    padding: 0;
    margin: 0;
}

li.token-input-token-mac span {
    color: #231C34;
    margin-left: 5px;
    font-weight: bold;
    cursor: pointer;
}

/* TOKENS */

li.token-input-token-mac {
    position: relative;
    display: inline-block;
    width: auto !important;
    font-size: 8pt;
    line-height: 12pt;
    margin: 0px 3px 3px 0px;
    padding: 4px 10px;
    background: none;
    background-color: #0F004E;
    color: #fefefe;
    cursor: default;
    float: left;
    font-weight: bold;
}

li.token-input-highlighted-token-mac {
    background-color: #231C34;
    color: #fefefe;
    font-weight: bold;
}

li.token-input-selected-token-mac {
    background-color: #231C34;
    color: #fefefe;
    font-weight: bold;
 }

li.token-input-highlighted-token-mac span.token-input-delete-token-mac {
    color: #fefefe;
    font-weight: bold;
}

li.token-input-selected-token-mac span.token-input-delete-token-mac {
    color: #fefefe;
    font-weight: bold;
}

li.token-input-input-token-mac {
    border: none;
    background: transparent;
    float: left;
    padding: 0;
    margin: 0;
}

li.token-input-input-token-mac input {
  width: 100px;
  padding: 3px;
  margin: 0;
}

div.token-input-dropdown-mac {
    position: absolute;
    border-top: none;
    left: -1px;
    right: -1px;
    background-color: #fefefe;
    overflow: hidden;
    cursor: default;
    font-size: 10pt;
}

div.token-input-dropdown-mac p {
    font-size: 8pt;
    margin: 0;
    padding: 0 10px;
    color: #fff;
}

div.token-input-dropdown-mac h3.token-input-dropdown-category-mac {
  font-size: 10pt;
  font-weight: bold;
  border: none;
  padding: 0 5px;
  margin: 0;
}

div.token-input-dropdown-mac ul {
    margin: 0;
    padding: 0;
}

div.token-input-dropdown-mac ul li {
    list-style-type: none;
    cursor: pointer;
    background: none;
    background-color: #fefefe;
    margin: 0;
    padding: 0 0 0 10px;
    color: #999;
    text-transform: uppercase;
}

div.token-input-dropdown-mac ul li.token-input-dropdown-item-mac span.token-input-dropdown-item-description-mac {
    float: right;
    font-size: 8pt;
    font-style: italic;
    padding: 0 10px 0 0;
    color: #999;
    text-transform: uppercase;;
}

div.token-input-dropdown-mac ul li strong {
    font-weight: bold;
    text-decoration: underline;
    color: #999;
    text-transform: uppercase;
}

div.token-input-dropdown-mac ul li.token-input-selected-dropdown-item-mac,
div.token-input-dropdown-mac ul li.token-input-selected-dropdown-item-mac.odd {
    background: #0F004E;
    color: #bb8322; //Official Red
    text-transform: uppercase;
    font-weight: bold;
}

div.token-input-dropdown-mac ul li.token-input-selected-dropdown-item-mac:hover,
div.token-input-dropdown-mac ul li.token-input-selected-dropdown-item-mac.odd:hover,
div.token-input-dropdown-mac ul li.token-input-selected-dropdown-item-mac:focus,
div.token-input-dropdown-mac ul li.token-input-selected-dropdown-item-mac.odd:focus {
    color: #fff;
 }

div.token-input-dropdown-mac ul li.token-input-selected-dropdown-item-mac span.token-input-dropdown-item-description-mac,
 div.token-input-dropdown-mac ul li.token-input-selected-dropdown-item-mac.odd span.token-input-dropdown-item-description-mac {
    color: #fff;
}

来源：https://stackoverflow.com/questions/39217439/how-to-modify-jquery-token-input-css-to-add-a-tiny-rectangle-around-the-x-to-can