Styling the first option of a <select> input on iOS - iphone

Question

I'm trying to style a select input on iOS. The first option or initial state should have smaller font-size but not the rest of the options.
I have the following html structure:
<select class="dropdown">
<option selected="" value="Navigation">Navigation</option>
<option value="some-link">Whatever</option>
<option value="some-link">Another option</option>
<option value="some-link">Why</option>
<option value="some-link">What</option>
</select>
My CSS for it looks like this:
select {
-webkit-appearance: none;
font-family: 'Custom-Font', sans-serif;
font-size:.5em
line-height:1.8em; // optical center
background-color: #ccc;
color: #333;
border: none;
padding: 6px 10px 4px 10px;
}
.dropdown {
background-image: url(img/assets.svg);
background-position: right 2px;
background-repeat: no-repeat;
width: 100%;
display:block;
margin-bottom:-1.5em;
option:not(:first-of-type) {
font-size:1.5em;
}
}
The <select> menu looks exactly like I want it to look. It says "Navigation" inside a light-gray box with a rather small font-size.
However when clicking/tapping the select on my iphone the native UI view of iOS shows all options also in a very small font-size.
How can I just make the selected option (or the box itself) use the custom formatting but not the options. I want my options to have a "normal" readable font-size.
Any ideas on that? I tried with option:not(:first-of-type) and increase the font-size but no effect!

Answer 1

Unfortunately, there isn't a way to do it. iOS Safari takes full control of styling select lists' internal contents. Here's a reference for verification: little link.
One way to achieve this this would be to simulate the dropdown/select menu using JavaScript.
It's not very preferable, but if you absolutely require to change the default styling, then I'm afraid it's the only way to go; here's a demo that should give you an idea on how to do the simulation: another little link.

Answer 2

Try this 100% worked for me
select {
-webkit-appearance: none;
-moz-appearance: none;
appearance: none;
}

Answer 3

For what it's worth - I had a transparent <select> dropdown with a border radius when closed. On iOS (I'm not sure about android, I didn't test it) the default grey box for the <select> would appear inside of my custom border which was unappealing and unwanted.
To get rid of the inner grey box I used the following CSS:
-webkit-appearance: none;
And further more - pertaining to this OP's topic. Bootstrap offers a convenient solution with great documentation to enable custom dropdowns with Javascript. Check it out here.