add a wrapper

Hi.

I think I like Uptown Style. However, I have one issue that I have been trying to fix on the website that I am building. I think that what I want to accomplish is this:

I would like the whole page to be within a wrapper / set of tables. The reason is that I want to put a limit to the pagetitles/hero (the area in the preset that contains flowers). Also, I want to be able to control this by pixels and percent, making it appear different depending on screen size. So that it is allowed to extend into the margin on a mobile phone, but on a big screen is limited.

Further. The main content area below question is controlled by the following css. Maybe that will be afflicted by the changes that I want specified above?

.content-area {
width: 60% !important;
max-width: 70% !important;
margin: 0 auto !important;
float: none !important;
}

@media only screen and (max-width: 768px) {
.content-area {
width: 100% !important;
max-width: 100% !important;
}
}

Any help appreciated!
Best.