I had this idea to use a track matte technique from After Effects (or a clipping mask in photoshop) to make a cool effect using just HTML and CSS.
This utilizes a 100% wide, 100% tall SVG image with text cut out from it. The background of the section that the image covers has an animated gradient using CSS3.The result is a really cool effect with unlimited creative possibilities.
You could change the size of the section to any proportion and not have this take up 100% of the screen size.