So I removed the sidebar and vertical bar and fixed the margins and padding, all using CSS, so I'm starting from a blank slate in Sugarcane. So far so good. I added a background image and the following CSS in a separate stylesheet from my main stylesheet (because I wanted to tag certain passages with this background, but not all passages):
background: [img[stars]] no-repeat center center fixed;
So far, so good.
I then went to add an image over the background image (in other words, I have a bunch of text, and then I have an image, and then I have more text, all set over the background image) and used <center> tags around the image because I wanted it centered on the screen. I also used <center> tags around the text.
The text was centered, but the image floated to the right. I haven't been able to figure out how to fix this. Is there a way to set in the CSS so that all images added in passages (vs. the background image) are centered? I want to use a few images, and I always want them centered, though I don't always want the text centered.