JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li class="key">Item 1</li>
    <li class="key">Item 2</li>
</ul>

CSS

.key {
   background-color: #FFFFFF;   
}

JavaScript

$('.key').click(function() {
      var $elem = $(this); 
       var oldBG = $elem.css('background-color');
       $elem.css('backgroundColor', '#FF0000');
    setTimeout(function() {
        $elem.css('background-color', oldBG);
    }, 1000);
     });