How to CSS abbr | Quality Abbreviations

Slightly lighter color (assuming your text is black), dotted bottom border, and a question-mark cursor. This has become a somewhat standardized approach, which is always a good thing in design usability.
abbr {
border-bottom: 1px dotted #222;
color: #222;
cursor: help;
}

Demo: Tutorial Quality Abbreviations

abbr {
border-bottom: 1px dotted #222;
color: #222;
cursor: help;
}