css - rgba is not working, when i had it working 5 minutes ago -

This is for my site, I need text that you can not see through the background image Which can be seen. It is not working on chrome or firefox; RGB will not work either, does it just say an invalid asset value? Why is it

This is my CSS:

  #top_box {background: rgba (208,206,195, .5); Status: Relative; Height: 400px; }    
 
 
 I am trying to use it and it seems that < Code> RGBA  and the left parenthesis, instead of:  
  Background: RGBA (208, 206, 195, .5);   
 Try ...  
  Background: RGBA (208,206,195, .5);