Quick CSS for checkout page modifications

Reposting as my original post did not get a response.

I set up a staging/test site to test code offered on this site.

All the code works except for one piece. The code to set up the two columns does not seem to be right.
The staging site is in the private content. How should I adjust the code outlined in the article to achieve the the 2 column look?

This is the portion of CSS that is supposed to achieve the 2 colum look.

“Now, we’ll get rid of that big blank space by moving the “Ship to a different address” section below the “Billing” details and shifting the “Your Order” section up to the right side of the page.”

.woocommerce-checkout .woocommerce .col2-set { width: 47%; float: left; margin-right: 4%; }
.woocommerce-checkout .woocommerce .col2-set .col-1,
.woocommerce-checkout .woocommerce .col2-set .col-2 { margin-bottom: 2em; width: 100%; float: none; }
.woocommerce-checkout #order_review_heading,
.woocommerce-checkout #order_review { background: #fff; width: 47%; float: right; margin-right: 0; }