Collapse header on scroll exploration

There are a lot of concerns about the vertical space that we use for our header and navigation. A put together this rough exploration of showing how we could easily save 100px or so, while still keeping the same functionality. The concept is that half of the header scrolls off on scroll down, but you can easily access it again with a quick scroll up.

Please view the full animation here: https://drive.google.com/file/d/0B-PqsmU0p5QVb1lZMTNBa2NoZ28/view?usp=sharing

The timing and details in this example are rough and would need to be refined if we pursue this concept. We would also have to explore what happens at some smaller screen resolutions.