<style>
select::first-letter, option::first-letter { color:green; }
.block select, .block option{ display:block; }
.scroll select, .scroll option{ display:block; overflow:hidden; }
</style>

<select></select>
<select>F</select>
<select>Ff</select>
<select><option>F</select>
<select><option>Ff</select>

<div class="block">
<select></select>
<select>F</select>
<select>Ff</select>
<select><option>F</select>
<select><option>Ff</select>
</div>

<div class="scroll">
<select></select>
<select>F</select>
<select>Ff</select>
<select><option>F</select>
<select><option>Ff</select>
</div>

<select size=2></select>
<select size=2>F</select>
<select size=2>Ff</select>
<select size=2><option>F</select>
<select size=2><option>Ff</select>

<div class="block">
<select size=2></select>
<select size=2>F</select>
<select size=2>Ff</select>
<select size=2><option>F</select>
<select size=2><option>Ff</select>
</div>

<div class="scroll">
<select size=2></select>
<select size=2>F</select>
<select size=2>Ff</select>
<select size=2><option>F</select>
<select size=2><option>Ff</select>
</div>