What's the difference between saying element1, element2 {display: inline block;} and element1 + element2 (display: inline block;)?

Question

What's the difference between

 element1, element2 {display: inline block;}

and

element1 + element2 (display: inline block;)

in terms of display?

Answer 1

element1 , element2: both elements have same class(style), also you can do like this:

element1, element2 {display: inline block;}

or

element1 {display: inline block;}
element2 {display: inline block;}

element1 + element2: + is for next sibling, all element2 that are placed immediately after element1

Answer 2

"+" is the adjacent sibling selector. It will select any element DIRECTLY AFTER element (not a child or parent though, a sibling).