Does font size control width of whole site?

I like your Theme very much – although I decided to change a few things for certain reason. But I really have difficulties in locating the right screws:
– When I reduce font size the overall width of the site is also affected. Where/how can I reduce font size independent from other elements?
– I youse “posts” not as posts, but as a portfolio of my projects – each “post” represents one projekt. I managed to hide post tags with CSS:

.post-meta li.tags {
	position: absolute !important;
	clip: rect(1px 1px 1px 1px); /* IE7 */
	clip: rect(1px, 1px, 1px, 1px);
}

In an analog way I also banned Categories, author, and comments – but I failed at post date (top left), last-post-/ next-post-button and “comments are disabled”. Can you tell me how to hide them, too?

Thanks a lot, James, and a happy new Year to you and everybody reading this!