yui/yui3 — comment on commit e1d2c90eed2334936210d1e1c6c53a43934ed517
File: src/button/css/cssbutton.css line 24
By msweeney:

As Ryan mentioned, the YUI convention is to use the asterisk property prefix ("*color") for IE 6&7, and the underscore prefix ("_color") for IE <=6.

You should declare the fallback color first, then use rgba, which will be disregarded by IE 8 as an invalid value, followed by the IE6/7 rule:
```
color: #444; /*rgba not supported (IE 8) */
color: rgba(0, 0, 0, 0.80); /* rgba supported */
*color: #444; /* IE 6 & 7 */
```