title: Nav bar moves to the top when page is scrolled down
body: <p>Found this page recently and wanted to copy its navigation bar for my website.</p>
  
  <p>As you notices, when the page loads the navigation bar uses a transparent background and is has padding. But when the user scrolls down, the bar slides up and sticks to the top. Pretty amazing!</p>
  
  <p><a href="http://whois.domaintools.com/" rel="nofollow">http://whois.domaintools.com/</a></p>
  
  <p>If I'm not wrong bootstrap was used for the navigation bar itself but I have no idea how they make it slide to the top when scolling down.</p>
  
  <p>Any one has any idea how this can be accomplish?</p>
  
  <p>Thanks
  JIACHEN:)</p>