Then go for a walk. Use the largest, most colorful screen available. This book can be read on small phone screens and monochrome readers, but you'll be happier if things appear in color on a larger screen. I use color as an important teaching tool, so if you're reading in black-andwhite, you're sacrificing some of the extra teaching value of a full-color ebook.
Colored elements do show up as a lighter shade on some black-and-white screens, and on those devices the effect isn't entirely lost, but full color is better.
As for reading on a larger screen— the book includes more than 2,000 lines of example code. Small screens break long lines of code into awkward, arbitrary segments, jumbling the formatting. While still decipherable, the code becomes harder to read. If you don't have a mobile device that's ideal for this book, consider installing the free Kindle reading app on your laptop. If you're reading on a mobile device, go horizontal. For some reason, I resist doing this on my iPad unless I'm watching a video.
But even I, Vern Vertical, put my tablet into horizontal mode to proof this book.
So please: starting with Chapter 1, do yourself a favor and rotate your tablet, reader, or phone to give yourself a longer line of text. It'll help prevent the unpleasant code jumble mentioned above.