The hero-unit class calls in Bootstrap CSS rules that scale up font sizes, creating a welcome message that can't be missed. You'll note that things aren't too large outside the hero-unit in the headings and paragraphs below. Here live example
As seen in the example, you can set the width of the header to the full width of the screen just by changing the structure of the html code.
You can change the width of the hero-unit by wrapping in standard class="span.." and add any items such as the Sign in form as shown in the example
Live demo
Change hero-unit background color
You can change padding spacing, and background color in the stylesheet
