Khan Academy
Khan Academy: Webpage Design
Tips and tricks to making webpages look good include fonts, colors, whitespaces, and templates and frameworks.
Khan Academy
Khan Academy: Quick Tip: Selecting by Tag Name
In webpage design the CSS rule tells which HTML element to style by using selectors based on their tag names.
Other
O'reilly: On Lamp Ruby on Rails
An O'Reilly discussion of how Ruby on Rails works and how it fits into the open source LAMP stack.