I was easily able to make my entire site in Magento 2 from the default to 2columns-left by a few simple changes in the admin section.
I created my own theme with the fallback of the luna theme. All overrides and modifications were done in my new theme only.
However, when it comes to the customer/account/login page, it appears as a single column page with the login section at the top and the left menu bar spans the entire bottom of the screen.
How do I change the account/login page and the account/create pages to a 2column-left layout?