Thank you for this very handy post!

I’d like to give my two cents about the contents container.

I like to reduce the number of images as little as possible.

Instead of (or in addition to) using the ‘cream_dust_transparent.png’ image, you may want to consider this:

bc. .container-narrow { background-image: url(/img/cream_dust_transparent.png); background-image: rgba(255,255,255,0.8);
}

The use of “background-image” for a color is intentional, in order to provide an image fallback for browser that don’t support rgba().