New city design

Do not merge yet. 
Avoid nesting as much as possible. It will create problems in the future: http://csswizardry.com/2012/05/keep-your-css-selectors-short/

You can try adding a second class, eg. header-jumbotron (and you can go with either having 2 classes in the markup, or using extend and only use 1 class in the markup)