Light text on a dark background is a bad idea

Studies have shown that readers are 26% more accurate in reading when the text is dark characters on a light background.

Even more so, people with astigmatism (a mere 50% of the population) find it incredibly difficult to read light text on a dark background and often this results in a blurry reading experience for them. Add to this the shiny glass screen of an iPad, and it makes it almost impossible for someone to read your content without having to strain.

Reading text with a lighter background actually causes the iris to close more and decreases the effect of the impaired lens in their eye, and is a more pleasant reading experience for users without slight vision impairments so keep that in mind when designing your content.