I'd set the page background to match the green of the borders, center it, and keep the central column white.
Here's what it looks like on my screen (full HD):
screencap.jpg
Fully agree with the Wordpress suggestion. You can run it off of Wordpress' site, or you can install it server-side on your own webhost fairly easily.
It does take some time to figure out the CSS, though, if you want to customize your own theme. There may be some low-cost WYSIWYG editors out there that would help, but I always do all of my design in a text editor (in spite of having a license for Dreamweaver). Not that my web design is particularly good. Or adequate, even. But at least it keeps people from trying to hire me to design their websites when they see mine!