• MarkApp: Building apps with HTML. Widgets and libraries that can be used without writing any JavaScript.

• You Might Not Need JavaScript. Various widgets and libraries that are HTML/CSS only.

• Hint.css: Pure CSS-only tooltip library

Link colors

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

• Flexbox Cheatsheet

Animations

• Animista: Wizard that lets you browse and create keyframe-based animations

Twitter Bootstrap

• winjs/winstrap: The official Bootstrap theme for Microsoft's Modern design language

Ems for block widths

• 20 em ≈ 320px
• 30 em ≈ 480px
• 40 em ≈ 640px
• 50 em ≈ 800px
• 60 em ≈ 960px
• 64 em ≈ 1024px

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

CSS frameworks

Quoted file sizes are minified + gzipped.

• Bulma: CSS framework based on Flexbox. Has widgets available. 19.7 KB

• Pure.css. Minimal CSS framework, 3.8 KB. From Yahoo. 6 KB.