Question: why do my HTML table cells have a space around them? Why don’t the join up like a normal table?
Answer: the border-spacing attribute is not set to zero by default. Try setting it explicitly to 0em in the style sheet.
I can’t believe this has caught me out twice! I don’t understand why you would not want the border spacing to anything other than zero by default.
I found this site to be really helpful for understanding the table model in CSS.