One

background-color: #f2f2f2;
/* Sidebar */
background-color: #f7f7f7

text-color: black;

a:link { color: #1863a1 }
a:visited { color: #751590 }
a:focus { color: #0181eb }
a:hover { color: #0181eb }
a:active { color: #01579f }

Highlight styles

Lorem Ipsum e-mail: background-color: gold, which is the same as Gary Johnson's e-mail campaign: #FFD700

Highlight text-shadow, from http://www.audiocheck.net/testtones_highdefinitionaudio.php:

text-shadow: -3px 0px 3px yellow, 3px 0px 3px yellow, 6px 0px 6px yellow, -6px 0px 6px yellow;

Flexbox

Animations

Twitter Bootstrap

Ems for block widths

from Responsive enhancement

Clearfix

Clearfix is the original method for clearfix. At SitePoint, apparently using overflow: auto also works for container elements.

Spacing

letter-spacing: .06em