Modify Select So Only The First One Is Gray

Inspired from Fábio Silva's solution, a very cool solution using AngularJS:

select {
  color: #ccc;
}
option {
  color: #aaa;
}
option:first-child {
  color: #ccc;
}
select.ng-dirty {
  color: #aaa;
}

Here is a more modern solution so it's not specific to the first option, but rather an invalid option and requires no JS to show only the title/placeholder option as grey whereas the rest appear normal.

select,
select option {
  color: #000000;
}

select:invalid,
select option[value=""] {
  color: #999999;
}

label {
  display: block;
  margin: 16px 0;
}

/*Added for browser compatibility*/
[hidden] {
  display: none;
}

<label>
    Invalid option cannot be selected and is hidden from the user in the dropdown.
    <select required>
      <option value="" selected disabled hidden>Please select your favourite fruit</option>
      <option>Apple</option>
      <option>Banana</option>
    </select>
</label>

<label>
    Invalid option cannot be selected, but is not hidden from the user in the dropdown.
    <select required>
      <option value="" selected disabled>Please select your favourite fruit</option>
      <option>Apple</option>
      <option>Banana</option>
    </select>
</label>

<label>
    Invalid option can be selected and is not hidden from the user in the dropdown.
    <select required>
      <option value="" selected>Please select your favourite fruit</option>
      <option>Apple</option>
      <option>Banana</option>
    </select>
</label>

The :invalid selector on the select only works on an option if the select box is required and the selected option's value is empty, so you can style it as you would a text box's placeholder text.

Setting it to disabled prevents the user from selecting it in the select's options, and setting it to hidden hides it from the select's options.

Here is my CodePen demo that explores additional select box styles and shows this one in action on a light background.

September 2017 edit

You should take a look at Tessa's answer below, since it's CSS only and much better now! This answer is almost 5 years old now, so things have changed a bit. I'm keeping the original answer just for reference.

Original answer

I am closer to what you need:

You need to gray the entire SELECT (so that when it's closed, it is gray), then "un-gray" all the OPTION's (put them black) and gray the first-child. Something like this:

CSS

select
{
    color: #ccc;
}
option
{
    color: #000;
}
option:first-child
{
    color: #ccc;
}

EDIT So the edited code is:

HTML

<select onchange="changeMe(this)">
  <option selected disabled>Please select your favourite fruit</option>
  <option>Apple</option>
  <option>Banana</option>
</select>

Javascript

<script type="text/javascript">
    function changeMe(sel)
    {
      sel.style.color = "#000";              
    }
</script>

I've update jsFiddle. You can check it here: http://jsfiddle.net/s5Xy2/5/ ​

Notice that I've also changed the HTML part, because I think you want to use the "disabled" attribute (and because of that, you'll have to add the "selected" attribute also).

If you still want the pure CSS code, it's here: http://jsfiddle.net/s5Xy2/4/