Please can someone tell me how I can hide the border of some cells of a table, I am working on my webside and I would like to get this view, as you will see the table has been removed the border in some cells

Hi, I am working with several tables and text stantard to get the view I need, but even though I have configured the same width of the cells for the three tables in the browser the width varies, because this happens, as I can correct this?Can't you just use a multiple tables and create the headers with standard text?