Use a space or greater than sign > in CSS selector? [duplicate]

Answer 1

They mean two different things.

.welcome div means select any div which is a descendant of .welcome. So it would select all of these div elements:

    
Me
    
And me
        
And me
            
And me too!
        
    

.welcome > div only selects a direct child div of .welcome. So:

    
It selects me
    
And me
        
But not me
            
And not me either!
        
    

Have a read of http://css-tricks.com/child-and-sibling-selectors/ and https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Getting_started/Selectors