There are so many possibilities that it’s hard to decide what to do first. Still, we have to start somewhere, so let’s begin at the top of the calendar and then work on the grid of dates.
On the Use of cellspacing
The HTML-based cellspacing="0" is used because it’s the only widely supported way to control the spacing between table cells. CSS2 does have a mechanism for doing the same thing, but support is minimal. The HTML attributes cellpadding and border are both unnecessary, on the other hand, because support for the CSS properties padding and border is very widespread.
It’s probably easiest to set ...