For the Float Challenge -- I got this solution, got what I needed but is it correct?

It looks like you accomplished the objective, good job!

In programming, there's rarely only one "correct" way to do anything. But there are a few ways you can improve and optimize. When elements share the same class, you can avoid repeating yourself (known as making your code "DRY") by placing all the common attributes in one rule. Doing that here would look like this:

  .col {
    float: left;
    vertical-align: top;
    padding-left: 1em;
    padding-right: 1em;
    padding-bottom: 5px;
  }

  .col:first-child {
    width: 40%;
  }

  .col:last-child {
    width: 60%;
  }

This also replaces the adjacent sibling rule (".col + .col"). And it isn't necessary to float the columns on different sides, so I just let them share a "left" float.

In the next video you'll see how the instructor makes use of the unique classes of "primary" and "secondary" instead of the pseudo classes. But your use of the pseudo-classes is clever, and would be the perfect thing in situations where the elements don't have unique classes.

Keep up the good work, and happy coding!