Как записать в куки изменения шрифта?

 $(document).ready(function() {



   let btnFont = $('.font__item');
   btnFont.on('click', function() {
     let elem = parseInt($(this).data('font'));
     let value = (16 * (100 + elem)) / 100;
     $('html').css({
       'fontSize': `${value}px`
     });

     /*  let UTCDate = new Date(new Date().setFullYear(new Date().getFullYear() + 1)).toUTCString();
       document.cookie = `${name}=${value}; path=/; expires=${UTCDate};`;
       */
   })


 });

html {
  font-size: 16px;
}  

h3 {
  font-size: 2em;
}

p {
  font-size: 1.4em;
}

<div class="font__box">
  <button class="font__item" data-font="13%">btn 1</button>
  <button class="font__item" data-font="26%">btn 2</button>
  <button class="font__item" data-font="39%">btn 3</button>
</div>


<h3>titlr</h3>

<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Minima magni recusandae dolore, odit sunt perspiciatis sequi natus cupiditate ad officia, doloribus aperiam qui quibusdam voluptatem ullam vel, eum mollitia officiis?</p>

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>