Still wide enough, but quite close to the desired line length of 15 words max. Some browsers tend to collapse empty cells. So there needs to be something in it, preferably invisible. By now the page already has a shape quite similar to this site. One thing is still missing.
Tables have a default cell spacing and padding.
So adding up all numbers plus the spacing and padding, you would go overboard on 575. This still could mess up the exact layout. To further constrain the table both are set to zero. Now things will add up precisely.