style.css

/* Searchable select stuff */
.searchable-select input {
    /* Width can be configured to anything, but it needs to match .searchable-select ul */
    width: 200px;
    font-size: 1.1rem;
    font-weight: normal;
    color: darkslategray;
    border: 1px solid #ced4da;
}

.searchable-select .hidden {
    display: none;
}

.searchable-select ul {
    position: fixed;
    width: 200px;
    display: inline-block;
    list-style-type: none;
    border: 1px solid lightgray;
    border-top: none;
    max-height: 30vh;
    min-height: 5vh;
    margin: 0;
    padding: 0;
    overflow-y: auto;
}

.searchable-select ul li {
    cursor: pointer;
    font-weight: normal;
    border: 1px solid lightgray;
    border-top: none;
    border-left: none;
    color: darkslategray;
}

.searchable-select ul li.selected {
    background-color: blue;
    border: 1px solid lightgray;
    color: white;
}

.searchable-select ul li:hover:not(.selected) {
    background-color: lightgray;
}