position
Headers can be positioned on the page in a few different ways. By default, the header uses the "inline" positioning mode. In this mode, the header sits in the natural document flow (the default HTML behavior), which ensures that it is visible on all devices, regardless of JavaScript and CSS positioning support.
A "fixed" positioning mode fixes the header to the top of the viewport on browsers that support CSS fixed positioning (which includes most desktop browsers, iOS5+, Android 2.2+, BlackBerry 6, and others). In browsers that don't support fixed positioning, the header will fall back to static, inline position in the page.
Default value
Inline
Valid values
inline or fixed.