Why setAttribute is not setting class to li

Question

Actually, I'm learning DOM Manipulation. As you can see, I created the li element but the issue is it is not applying the fontSize to the li.

const title = document.querySelector("#main-heading");

title.style.color = "red";

const listItems = document.querySelectorAll(".list-items");
  
for (i = 0; i < listItems.length; i++) {
    listItems[i].style.fontSize = "2rem";
}
const ul = document.querySelector("ul");
const li = document.createElement("li");

ul.append(li);
li.innerText = "X-men"
li.setAttribute('class' , 'list-items' )

  

   <div class="container">
      <h1 id="main-heading">Favourite Movie</h1>
      <ul>
        <li class="list-items">The Matric</li>
        <li class="list-items">Star Wars</li>
        <li class="list-items">Harry Potter</li>
        <li class="list-items">Lord of the Rings</li>
        <li class="list-items">Marvel</li>
      </ul>
    </div>

Answer 1

Remove setting the font-size value inside for loop. Instead have it as separate css.

.list-items {
  font-size: 2rem;
}

Append the newly created li after the class is added.

ul.append(li);

Forked Example:

const title = document.querySelector("#main-heading");

title.style.color = "red";

const listItems = document.querySelectorAll(".list-items");
  
const ul = document.querySelector("ul");
const li = document.createElement("li");

li.innerText = "X-men"
li.setAttribute('class' , 'list-items');

ul.append(li);

.list-items {
  font-size: 2rem;
}

<div class="container">
      <h1 id="main-heading">Favourite Movie</h1>
      <ul>
        <li class="list-items">The Matric</li>
        <li class="list-items">Star Wars</li>
        <li class="list-items">Harry Potter</li>
        <li class="list-items">Lord of the Rings</li>
        <li class="list-items">Marvel</li>
      </ul>
    </div>