如何分别设置数组元素的样式

<div class="array-container">
  <span class="array-element">元素1</span>
  <span class="array-element">元素2</span>
  <span class="array-element">元素3</span>
</div>

.array-element {
  color: red;
  font-weight: bold;
}

<div id="array-container">
  <span class="array-element">元素1</span>
  <span class="array-element">元素2</span>
  <span class="array-element">元素3</span>
</div>

var arrayElements = document.getElementsByClassName("array-element");
for (var i = 0; i < arrayElements.length; i++) {
  arrayElements[i].style.color = "red";
  arrayElements[i].style.fontWeight = "bold";
}