added forms styles

Let's use a less variable for our re-used colors.  I've already created a `variables.less` file for us.  Many of our variables will be used across multiple files.  To keep that from getting tedious, it makes sense to them all in the same place.

Less variables look something like this:

``` less
@my-color: #0000ff;
```

The variables in our `variables.less` will be global (similar to JavaScript).  This gets unwieldy in large projects and when you need to use other libraries like Bootstrap because someone else may re-declare a variable, over-riding yours.  To deal with this we'll use namespacing, a unique prefix for us to keep our variables distinct.  Let's use `humble-`.  So variables will look something like `@humble-green: #39AE68;`.