This is a variable or event handle.
<div style="height: 200px;"> <p class="nebula-vmiddle">This is vertically centered.</p> </div>
Note: To use this class, the parent element must have a set height (not a min-height)!
Consider using flexbox properties for vertically centering and aligning. Bootstrap has classes that help use flexbox.
Located in /assets/scss/partials/_helpers.scss.