Create full width responsive website in Genesis Dynamik

Hi.
A client has requested (against my advice!) that I redesign her website to make it full width and responsive for different size desktop monitors (as well as mobile responsive). This works fine for the home page which is EZ as all the columns are in percentages. However on the content-sidebar and content-sidebar-sidebar pages/posts the sidebars are moving under the content.
My objective is to keep the primary sidebar at 340px and the secondary sidebar at 180px and to vary the width. On the widths screen I have used these widths plus a content width to give a total width of 1900px (on the basis that most monitors aren't larger than 1920px). The wrap is set as fluid.
I have successfully used the following CSS to make the header fit correctly:
.content-sidebar .site-header .wrap, .content-sidebar-sidebar .site-header .wrap {
width: 100%;
}
However, I am struggling to find the necessary CSS to make the content resize to enable the sidebars to remain alongside.

Please can you suggest CSS that will make this work?

Thanks

Fiona

@Fiona

Can I get a link to the site? You can email it if it's private.

@eric
Hi Eric. Thanks for your reply, and sorry for the slow response, I have only just picked this up.
The client decided not to proceed any further with the redesign of the website (frustrating as I had put in a considerable amount of time!), and as I have had to make other substantial changes to the current site I have overwritten the staging site so there is no longer a link I can give you. I have a backup of the site to where I got to in case she changes her mind again and wants to go back to it....

@Fiona

Well that's' frustrating for you, I know. Sorry to hear that. Either way, we're here if you need us. 🙂