JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="style.css">

<div class="dropdown" id="dropdown">
    <input type="text">
    <div class="options">
        <fieldset></fieldset>
        <fieldset>
            <label data-value="111">
                <input type="checkbox" required>
            </label>
        </fieldset>
        <fieldset>
            <label data-value="222">
                <input type="checkbox" required>
            </label>
        </fieldset>
        <fieldset>
            <label data-value="333">
                <input type="checkbox" required>
            </label>
        </fieldset>
        <fieldset>
            <label data-value="444">
                <input type="checkbox" required>
            </label>
        </fieldset>
        <fieldset>
            <label data-value="555">
                <input type="checkbox" required>
            </label>
        </fieldset>
    </div>
</div>

CSS

body{
    display: flex;
    align-items: center;
    justify-content: center;
}

#dropdown{
    border: 1px solid;
    width: 200px;
    border-radius: 2px;
}
#dropdown fieldset:hover{
    background-color: #dadada;
}
#dropdown fieldset label{
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    text-indent: 10px;
}
#dropdown fieldset{
    margin: 0;
    padding: 0;
    border: 0;
}
#dropdown .options > fieldset:valid{
    background: #dadada;
    margin-right: 2px;
    border-radius: 2px;
    padding: 0 4px;
}
#dropdown .options > fieldset:valid label{
    text-indent: 0;
}
#dropdown .options > fieldset:not(:first-child):valid{
    height: 15px;
    font-size: 14px;
    background: #545353;
    color: #fff;
    font-family: Arial;
    cursor: pointer;
}

/* Логика */
#dropdown{
    position: relative;
    --item-height: 30px;
    --list-height: 200px;
}
#dropdown [data-value]:before{
    content: attr(data-value);
}
#dropdown input{
    opacity: 0;
    position: absolute;
}
#dropdown,
#dropdown .options fieldset{
    height: var(--item-height);
}
#dropdown .options{
    display: flex;
    position: absolute;
    flex-wrap: wrap;
    width: 100%;
    top: 0;
    overflow: hidden;
    max-height: var(--item-height);
    transition: 0s .1s max-height;
}
#dropdown > :focus + .options{
    max-height: var(--list-height);
    overflow-y: scroll;
}
#dropdown > input:not(:focus){
    width: 100%;
    height: 100%;
    display: block;
    z-index: 3;
}
#dropdown > input{
    position: relative;
}
#dropdown .options > fieldset:invalid{
    order: 2;
}
#dropdown fieldset{
    flex-basis: 100%;
}
#dropdown .options > fieldset:valid{
    flex-basis: 10%;
    z-index: 3;
}
#dropdown .options > fieldset:first-child{
    flex-basis: 0;
    padding: 0;
}