The design is very, very nice. So not much to improve on there :)

Some suggestions,

1. Add headers i.e. <h1><h2><h3>...

2. Move your CSS into it's own file. No need for poeple to keep downloading style information on every page.

3. Define your font. Didn't look at the source, but menu font is different in Opera browser, not a big deal but a pretty easy fix.

4. You could add validation.

5. Fix this "Vision,mission&values"

6. Maybe capitalize all words in your menu, for example "Gateway to Life"

7. Let people know what section they are in somehow, either by making the titles match the menu names or highlight a menu section.

Good luck with your site!