The Boundless splash page is a simple, clean, one-page template by Kat Suricata (whose site is a good live example of it). It is licensed under a Creative Commons Attribution 4.0 International License. It is responsive (try it out; resize this window), and made with fully-valid HTML5/CSS3 code. It works well with every modern rendering engine and degrades legibly on older browsers (to a reasonable point). Download the template here.