CSS Problem with Space Between Tags

Please help me how to remove the vertical space between the header and the nav tag ?
Why is there a space between that ?
Here is the link: http://codepen.io/hungnguyen1895/pen/MpaxGY

Try setting the “Start a Free Trial” heading’s top margin to 0.

That’s right, After setting the heading margin to 0, the space disappeared.

Add this class right here to your CSS

.container h1 {
  margin-top: 0;

Hope this Helps!