Design

• Dochub.io

Basics

tag
.class
#id

display: block - default 100% width 
display: inline - consumes width of content

position: absolute - out of flow

Guides

• http://www.youtube.com/watch?v=_mgyfwYKpmQ

• http://www.w3.org/wiki/Floats_and_clearing

Header, footer

• http://stackoverflow.com/questions/643879/css-to-make-html-page-footer-stay-at-bottom-of-the-page-with-a-minimum-height

Typography

• http://drewish.com/tools/vertical-rhythm

Accessibility

Headings should not be removed using display:none, because it removes the headings from assistive technology. Instead headings can be made invisible to sighted users using CSS class="element-invisible". [1]

Tools

• ColorZilla Ultimate CSS Gradient Generator