Rewrite CSS.

Visually separate page contents from whitespace by using a darker background
color. Add a border and border-radius to the page body. Ensure browser viewport
does not touch page body when the viewport is small. Make CSS more readable, and
add a few comments explaining what's going on.
Update site contents

Rearrange information. Move the "About Mike" section to `about.html`. Change the
contact information from a series of paragraphs to a definition list, and inform
visitors that the most effective method of getting in touch is by phone. Rewrite
some page titles, especially on the acknowledgements page. Tweak the wording of
several paragraphs.
Rewrite readme.

Shorten it significantly.