JSFiddle - React, Tailwind, and code Playground

HTML

<div data-role="footer" data-position="fixed" data-theme="c" data-tap-toogle="false">
			<div data-role="navbar" data-grid="b">
    				<ul>
      				   <li class="ui-disabled"><a id="listSO_options">Opções</a></li>
     				   <li><a class = "ui-btn-active  nav" href="#">menu</a></li>
   					   <li><a class = "nav" href="#" id="listSO_btnDef" data-icon="gear">Definições</a></li>
   					</ul>
			</div>
		</div><!-- footer -->

JavaScript

$('[data-role="navbar"] li:first').css('opacity', 1);