Just a heads up. When creating a 0 degree gradient Illustrator leaves out a very important css command. Which makes the gradient repeat itself.
To have a smooth single gradient you need to add repeat: fixed; to the background CSS command.
Example:
background : linear-gradient(0deg, rgba(255, 255, 255, 100) 0%, rgba(0, 0, 0, 100) 100%) repeat fixed;
This example was tested in firefox.
