On uploading a new post, my browser seemed to freeze. So I restarted the browser and my blog disappeared! The admin pages are all accessible, so I tried deleting the new post, deleting the new image, swapping for the parent theme and then back to my child theme, turning off out-of-date plugins, then updating out-of-date plugins and turning them off again... but still no visible blog!
What could have possibly happened? I didn't mess with any style sheet or php file directly, only tried to post a simple jpeg with a title!! I don't even know where to start to fix this.