superstar.css

.ms-options-wrap,
.ms-options-wrap * {
    box-sizing: border-box;
}

.ms-options-wrap > button:focus,
.ms-options-wrap > button {
    position: relative;
    width: 160px;
    text-align: left;
    border: 1px solid #9ebbd5;
    background-color: #fff;
    padding: 5px 20px 5px 5px;
    margin-top: 1px;
    font-size: 13px;
    color: #9ebbd5;
    outline: none;
    white-space: nowrap;
}

.ms-options-wrap > button:after {
    content: ' ';
    height: 0;
    position: absolute;
    top: 50%;
    right: 5px;
    width: 0;
    border: 6px solid rgba(0, 0, 0, 0);
    border-top-color: #9ebbd5;
    margin-top: -3px;
}

.ms-options-wrap > .ms-options {
    position: absolute;
    left: 0;
    width: 275px;
    background: white;
    z-index: 2000;
    border: 1px solid #aaa;
    text-align: left;
}

.ms-options-wrap > .ms-options > .ms-search input {
    width: 100%;
    padding: 4px 5px;
    border: none;
    border-bottom: 1px groove;
    outline: none;
}

.ms-options-wrap > .ms-options .ms-selectall {
    display: inline-block;
    font-size: 1.1em;
    /*text-transform: lowercase;*/
    text-decoration: none;
    cursor: pointer;
    font-weight: bold;
}

.ms-options-wrap > .ms-options .ms-selectall:hover {
    text-decoration: none;
    font-weight: bold;
}

.ms-options-wrap > .ms-options > .ms-selectall.global {
    margin: 5px 5px;
    cursor: pointer;
    font-weight: bold;
}

.ms-options-wrap > .ms-options > ul > li.optgroup {
    padding: 5px;
}

.ms-options-wrap > .ms-options > ul > li.optgroup + li.optgroup {
    border-top: 1px solid #aaa;
}

.ms-options-wrap > .ms-options > ul > li.optgroup .label {
    display: block;
    padding: 5px 0 0 0;
    font-weight: bold;
}

.ms-options-wrap > .ms-options > ul label {
    position: relative;
    display: inline-block;
    width: 100%;
    padding: 4px 4px;
    margin: 0px 0;
}

/*.ms-options-wrap > .ms-options > ul li.selected label,.ms-options-wrap > .ms-options > ul label:hover {
    background-color: #efefef;
}*/

.ms-options-wrap > .ms-options > ul input[type="checkbox"] {
    margin-right: 5px;
    position: absolute;
    font-weight: bold;
    left: 2px;
    top: 2px;
    transform: scale(1.2);
}

.ms-options-wrap * li {
    background: #ececec;
    border-bottom: 1px solid #FFFFFF;
}

/* select alternating items starting with the second item */
.ms-options-wrap * li:nth-of-type(2n) {
    background: #d3dbe4;
    border-bottom: 1px solid #FFFFFF;
}

.ms-options-wrap li[disabled] {
    opacity: 0.4;
    pointer-events: none;
}