HTML5 Boilerplate

The web’s most popular front-end template.  HTML5 Boilerplate helps you build fast, robust, and adaptable web apps or sites. Kick-start your project with the combined knowledge and effort of 100s of developers, all in one little package.

CSS-Tricks - A Complete Guide to Flexbox

The Flexbox Layout (Flexible Box) module (currently a W3C Last Call Working Draft) aims at providing a more efficient way to lay out, align and distribute space among items in a container, even when their size is unknown and/or dynamic (thus the word "flex").

MultiMarkdown 5

Markdown is a text-to-HTML conversion tool for web writers. Markdown allows you to write using an easy-to-read, easy-to-write plain text format, then convert it to structurally valid XHTML (or HTML).  Markdown is great, but it lacked a few features that would allow it to work with documents, rather than just pieces of a web page. MultiMarkdown ... extend it to work with complete documents that could ultimately be converted from text into other formats, including complete HTML documents, LaTeX, PDF, ODF, or even (shudder) Microsoft Word documents

Smashing Magazine

Founded in September 2006, Smashing Magazine delivers useful and innovative information to Web designers and developers. Our aim is to inform our readers about the latest trends and techniques in Web development. We try to persuade you not with the quantity, but with the quality of the information we present. Smashing Magazine is, and always has been, independent.