JSFiddle - React, Tailwind, and code Playground
HTML
<div class="a1">
<div class="a11">
<a href="a.php">A</a>
</div>
<div class="a12">
<a href="b.php">B</a>
</div>
</div>
CSS
.a11 a:hover, .a12 a:hover,.hovered { color:red;}
JavaScript
$( function(){
$('.a11 > a').on('mouseenter', function(){
$(this).parent().next('div').find('a').addClass('hovered') ;
}).on ('mouseleave', function(){ $(this).parent().next('div').find('a').removeClass('hovered');})
});