Is there an idustry standard for page widths for responsive sites?
 

When building a responsive site, are there some fixed widths most websites stick too? Is there an industry standard for this? For example 3 widths for large PC screen or laptop, e.g. 1920 / 1400 / 1000 px and two for tablets (horizontal/vertical) and two for smartphones (horizontal/vertical)?

sure just go to a site test site and they have all the sizes.
just google it
https://www.browserstack.com/responsive

look at:

https://www.awwwards.com/what-are-fr...eb-design.html

use best framework and you have all sorted

100%:thumbsup - Grids are the way it all works - Wordpress themes are almost all responsive these days - You can do almost anything with them and they will work anywhere...

Thanks guys, I am going to read about the frameworks!

Also the guy building sites for me sent me this page, it is very interesting as well and explains the difference between adaptive and liquid/fluid response, it turns out that we were after an adaptive page layout but just didn't know it was called that way.

blog . teamtreehouse.com/which-page-layout

We used WP sites in the past but our video and photo content sites are MySQL based with custom content management scripts and combining that with WP can be very tricky, before you know it you are a slave of WP and converting everything you built in the past to work with WP... I will avoid that from now on. For other things WP can be great.

Or did you mean using WP theses to add a certain design and behavior to an existing non-WP website?

instead of PX use %

what ^^ said

and for font sizes use em. i guess.