Due to inconsistency of CSS3 implementation across different web browser, I wish to leave some note on Gradient and Transparency.

Transparency

background: rgba(0,0,0,0.3);
background:transparent;
filter:progid:DXImageTransform.Microsoft.gradient(startColorstr=#50000000,endColorstr=#50000000);

Gradient

background: -moz-linear-gradient(rgba(255,131,126,1) 0%, (255,131,126,0) 95%;
background: -webkit-gradient(linear, left top, left bottom, 
from(rgba(255,131,126,1)),to(rgba(255,131,126,0)));
background:transparent;
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr=#FFFF837E, endColorstr=#00FF837E);

References:

  1. MSDN http://msdn.microsoft.com/en-us/library/ms532930.aspx
  2. Stackoverflow http://stackoverflow.com/questions/2293910/css3-transparency-gradient
  3. CSS Tricks http://css-tricks.com/rgba-browser-support/