JSFiddle - React, Tailwind, and code Playground

HTML

<form action="/echo/html/">
    <select id="idselect" class="ui-corner-all ui-widget-content" multiple="multiple" name="idselect[]">
        <option value="1">Opção 1</option>
        <option value="2">Opção 2</option>
        <option value="3">Opção 3</option>
        <option value="4">Opção 4</option>
    </select>
    <p>
        <button type="submit">Enviar</button>
    </p>
</form>

CSS

#idselect {
    padding: 3px 4px;
}