No I'm not saying that basic HTML isn't compatible with Safari, I'm saying that you need to provide widths for your columns otherwise each browser will just do whatever it wants with the table data. Safari is seeing a huge batch of text so it's using that as the priority, and then making everything else just fit into the space that's leftover.
The canvas size you've selected has absolutely nothing to do with each table cell's width.
Did you try the suggestions I provided above?
however, it may be that you haven't assigned a width to your td's or maybe that you've left aligned the text box.