I was looking at a writing contest which involved writing a short fiction story in a fantasy realm. The page that listed contest rules also had a number of helpful suggestions for the writers.
There were multiple suggestions all hovering around the same idea: Don't make your background look like parchment; Don't make your text look like handwritten script; Don't send in handwritten script; Use a white background with a reasonable-sized font in a .doc format.
They don't explicitly say it, but the message rang loud and clear: This is exclusively about content. Leave all of your design and visual effects out of it.
In the grand scheme of things, design and layout does matter. Even something as simple as a business thank-you letter should look nice. It makes a difference, even to people who are not cognizant of it. However, in the digital world, forms and layouts are completely malleable. And if you have somebody else who will be doing that job, then it is not your concern.
Worry about content, first and foremost. It is literally the most important part of writing. Design and layout is done even after editing and proofreading, if done at all.