title: Create nav bar that appears after scrolling to second section
body: <p>I need to create something like <a href="http://www.andreagalanti.it/lab/flatfy/" rel="nofollow">that</a> </p>
  
  <p>What I understand is that no matter the window size, the background is resized to fit perfectly and once I scroll down the nav bar becomes visible and sticks to the top.</p>
  
  <p>I believe I am going to need javascript (?) and obviously HTML and CSS. </p>
  
  <p>Any tips, even to what to search will be greately appreciated. </p>