Best way to widen TwentyTen

The main problem here is that the page scrolls almost by itself when content goes below the fold of the browser.

I’m on Firefox on a Mac. But just realized something. I’m using a mouse that has a horizontal finger scroll so maybe I’m worrying too much. If you make the browser really narrow there’s no horizontal scroll bar but I can still scroll it sideways. If you go here https://2010dev.wordpress.com/ and do the same thing, there’s a horizontal scroll bar.

I had the same problem with this site https://dev.senensky.com/ and I got this reply and it worked:

Your div #content has two margins applied to it, id remove the one from line 73. Also your div #colophon in the footer has a fixed width exceeding the containers width, I’d remove that on line 176 so it’s this…

#access .menu-header, div.menu, #branding, #main, #wrapper {
margin: 0 auto;
width:1156px;
}

Make these changes and see what happens. It seems to work on that page for me.

#container {
margin: 0;
width: 710px;
}

I changed it to this and still does it. You can check it now.
#container {
background-color: #ffffff;
float: right;
margin: 0;
width: 710px;
}

The horizontal scrolling that I was seeing earlier is gone, but I suspect that the reason that the horizontal scroll bar is not appearing has to do with the fact that this was originally a “reactive” designed theme that would widen and narrow with the browser window and I’m not sure what would have to be changed to fix that. I suspect it might be something in some of the PHP files.

The change we made though cleans things up considerably and keeps things within the wrapper. It might not have fixed the issue, but it did fix some issues.

I’m afraid I’ve reached the edge of my abilities on this one.

I really appreciate your time involved in helping me. I think learning media queries will help this kind of thing.