Example of a table with round borders:

Small radius
Text-text-text-text
Text-text-text-text
Text-text-text-text
Text-text-text-text
Text-text-text-text
Text-text-text-text


Larger radius
Text-text-text-text
Text-text-text-text
Text-text-text-text
Text-text-text-text
Text-text-text-text
Text-text-text-text



The key is in the CSS style "border-radius".
code for the above examples:
style="border-style: solid; border-width: 1px; border-radius: 50px; border-color: #f00;"