CSS Background Opacity [duplicate]

Children inherit opacity. It’d be weird and inconvenient if they didn’t. You can use a translucent PNG file for your background image, or use an RGBa (a for alpha) color for your background color. Example, 50% faded black background:

Set line spacing

Try the line-height property. For example, 12px font-size and 4px distant from the bottom and upper lines: Or with em units

How to change CSS using jQuery?

Ignore the people that are suggesting that the property name is the issue. The jQuery API documentation explicitly states that either notation is acceptable: http://api.jquery.com/css/ The actual problem is that you are missing a closing curly brace on this line: Change it to this: Here’s a working demo: http://jsfiddle.net/YPYz8/

Center image using text-align center?

That will not work as the text-align property applies to block containers, not inline elements, and img is an inline element. See the W3C specification. Use this instead: