fixed button width on a single page

Hi, My first question here and I am only just learning about CSS.I am trying to get several buttons on a page to be the same width so that it looks better. I have seen several posts about this but can't get them to work. I think it may be something to the first part of the code immediately after the # in some suggestions as I don't know what this refers to.I only really want this to fix the width on a particular page as there are other pages on the site that have buttons I would rather not have affected. The url is https://www.ruralministries.org.uk/regionalconferences2020

I hope that is enough info for someone to be able to help.

ThanksNick

That's brilliant - looks much better. Thank you @tuanphan

Thank you @tuanphan I used the same trick.