Using the blockquote for error/success/warning messages. I made cross-browser mixin for properties which require a swoth of vendor prefixes, like box-sizing & box-shadow in this case.
See the Pen by BJack (@BJack) on CodePen.
Blockquote Styling on CSS
CSS3 Error / Success Messages
Simple blockquotes
Dynamic SlideShow: LESS/Jade/JS
SVG background image
Fix for reblogs in Tumblr themes
Simple elegant blockquotes
Formatting blockquotes with CSS Grid
A blockquote style
Material Design Blockquote
Fancy Blockquote
Blockquote with SVG Data URI
Automatic Quotes
Damn simple blockquote
Simple Blockquote Slickness
Fancy Blockquotes
Blockquote
Blockquote Pullquotes
Alternating Blockquotes
<blockquote>
Fancy Blockquote Style
Responsive blockquote using elementQuery
Blockquote Auto Tweet Button