How to show the first N elements of a block and hide the others in css?

I am trying to hide the first 3 elements having the class .row inside the block .container.

What I'm doing is hiding all the .row first, and then I am trying to display the first 3 .row by using .row:nth-child(-n+3)

jsfiddle here: http://jsfiddle.net/z8fMr/1/

.row {
  display: none;
}

.row:nth-child(-n+3) {
  display: block;
}

<div class="content">

  <div class="notarow">I'm not a row and I must remain visible</div>
  <div class="row">Row 1</div>
  <div class="row">Row 2</div>
  <div class="row">Row 3</div>
  <div class="row">Row 4</div>
  <div class="row">Row 5</div>
  <div class="row">Row 6</div>

</div>

I have two problems here:

1. Row 3 is not displayed, am I using nth-child in the wrong way?
2. Is there a better practice than hiding everything and then creating a specific rule to display the n first elements that I want? Is there a way in css to just display the first 3 .row and then hide all the other .row ?

Thanks.

1. You have a .notarow as the first child, so you have to account for that in your :nth-child() formula. Because of that .notarow, your first .row becomes the second child overall of the parent, so you have to count starting from the second to the fourth:

    .row:nth-child(-n+4) {
        display: block;
    }
   

   Updated fiddle

<div class="content">
    <div class="notarow">I'm not a row and I must remain visible</div>
    <div class="row">Row 1</div>
    <div class="row">Row 2</div>
    <div class="row">Row 3</div>
    <div class="row">Row 4</div>
    <div class="row">Row 5</div>
    <div class="row">Row 6</div>
</div>

.row {
    display: none;
}

.row:nth-child(-n+4) {
    display: block;
}

2. What you're doing is fine.

You don't even need CSS3 selectors:

.row + .row + .row + .row {
    display: none;
}

This should work even in IE7.
Updated fiddle

Also, like Giovanni's solution, something like this could also work.

.container > .row:nth-child(3) ~ .row {
    /* this rule targets the rows after the 3rd .row */
    display: none;
}

I found this answer by Googling "css show first n elements", but the question now seems to be the opposite (hiding first n elements)

:nth-child(n+4)

^ this will work if you're looking for what I was looking for