Ideally, the base of this effect could be achieved using scroll-driven animations with additional JavaScript-based functionality considered progressive enhancement, but that has restrictions if the page has content beyond the main article (such as comments and navigation), where one must start implementing overflow: scroll hackery, so, alas, it currently requires JavaScript to achieve. Beyond trying to get you to the right page, my 404 page also has a style tag with display: block and the contenteditable attribute, which allows one to write their own CSS that’ll apply to the page. The site is split up into defined sections for each type of content (eg, posts, micros, photography, etc) with (sometimes paginated) top-level pages for each of them displaying a list of the content.