Then how to make them vertical align?

To vertically align two elements, you can use the CSS property `display: flex` on their parent container and set the `align-items` property to `center`. Here is an example:

HTML:

<div class="parent">
  <div class="child1">Element 1</div>
  <div class="child2">Element 2</div>
</div>

CSS:

.parent {
  display: flex;
  align-items: center;
}

This will vertically center the child elements within the parent container. You can adjust the `align-items` property to achieve different vertical alignments, such as `flex-start`, `flex-end`, or `baseline`.