This makes the buttons larger and easier to notice/click.

This patch contains a whole lot of layout improvements for the alps
theme, mainly replacing the table soup with flexbox and CSS grids, and
fixing up a number of loose ends. This gives us a lot more flexibility
over how the page is laid out. I also cleaned up a lot of other
low-hanging fruit in the layout & styles.

This causes the mailbox to automatically reload the page every 60
seconds, without JavaScript.

This also updates the base template data to include the full URL, and
replaces the earlier "Path" field with a pre-split array of path
components, which is more immediately useful to most templates given the
limitations of string munging with text/template primitives.