react-bootstrap-timezone-picker.min.css

.timezone-picker {
    display: inline-block;
    font: 13px sans-serif;
    position: relative
}

.timezone-picker-textfield input {
    width: 100%;
    padding: 9px 12px;
    font: inherit;
    box-sizing: border-box;
    outline: 0;
    background: #fff;
    border: 1px solid #e6ebec;
    border-radius: 2px
}

.timezone-picker-list {
    top: 100%;
    left: 0;
    right: 0;
    max-height: 200px;
    overflow-y: auto;
    margin: 0;
    padding: 0;
    border: 1px solid #e6ebec;
    margin-top: -1px;
    border-radius: 0 0 3px 3px;
    display: none
}

.timezone-picker-list-rel {
    position: relative;
}

.timezone-picker-list-abs {
    position: absolute;
    background-color: white;
    z-index: 2000;
    opacity: 0.99;
}

.timezone-picker-list-item {
    color: #444444;
    padding: 5px 12px
}

.timezone-picker-list-item-active {
    background: #ececec;
    cursor: pointer
}

.timezone-picker-open .timezone-picker-list {
    display: block
}

.timezone-picker-selected .timezone-picker-textfield input {
    color: #474747
}