Thank you so very much for your help! Fixing the doctype declaration at the top immediately fixed it for my phone browsers. I’ve sent a message to the person with the errors and it should most likely work.
I’ve gone and fixed as manyof the other errors as I could in this one sitting on the index page, which pretty much just consisted of my disregarding XHTML standards.
A lot of the remaining errors on the index page are involved in URL generation for sharing through social media, so I’ve left them untouched for now.
Once again, I can’t express my gratitude enough haha. Guess I’m still learning my way around.