Question

I don’t know how they are different in css

something
{
   //some properties
}

something >.somethingelse
{
   // something else's properties
}

and

something
{
   //some properties
}

something .somethingelse
{
   // something else's properties
}

I don’t know why there is such a > in the second case. Should there also be a < for use too ?

Answer 1

The > indicates that direct children somethingelse are found under something. Otherwise descendants will be found at all levels.

So using this following example:

<div class="something">
    <div class="somethingelse">
        <div class="somethingelse">
        </div>
    </div>
</div>

For the > example only the outer somethingelse div will take effect. For the example without > both divs will have the style applied.

< might imply a parent selector (ie apply a style to the direct parent of a matching class). I’m not aware of this existing yet, but theres an interesting post on it a csstricks here.