Trying to center blog post pagination with Will Myers split blog post plugin

Site URL: https://jls-portfolio.squarespace.com/portfolio/blog-post-title-two-9g694

Here is the page I'm working on right now: 

https://jls-portfolio.squarespace.com/portfolio/blog-post-title-two-9g694 (password: codehelp)

I'm using Will Myers' Blog Post Banner Image Styles plugin and the split screen style. I'm trying to center the blog pagination at the bottom of the blog post side of the screen (see example website image). I've tried a few things, and have managed to move the text over, but the text itself is not centered on the page.  

This is the CSS I've been using as a base to get the text somewhat in the right position. But I can't get it to center once I get to this step, even when targeting elements below this level (see image from my website). 

.wm-banner-style-3 main.container .item-pagination {
  right:50%;
  left:50%;
  padding:0;
  margin:4vw;
  display:block;
  white-space:nowrap;
}

Any suggestions would be greatly appreciated. 

UPDATE: I figured out how to center the text on a regular blog page for anyone interested in having centered pagination on their blog posts. I couldn't find a similar post when I did a search, so thought I would post the code for a regular blog post. I've attached a picture so you can see what looks like.

.item-pagination-link .item-pagination-icon {
  display:none;
}
.visually-hidden {
  position:relative !important;
  height:100% !important;
  width:100% !important;
  clip:auto;
  padding:10px 0 !important;
}
.visually-hidden:after {
  content: " Post";
  position:relative;
}
.item-pagination[data-collection-type^="blog"], .item-pagination[data-collection-type^="blog"] a {
  margin:0 auto 10vw;
  display:block;
}
.item-pagination-link {
  text-align:center;
}
.pagination-title-wrapper {
  margin-bottom:-10vw;
}

I'm going to see if I can now make this work with the plugin.