JSFiddle - React, Tailwind, and code Playground

HTML

<div class="register_account">
<form>
<select>
<option value="null">Select a Country</option>
<option value="AX">Ă…land Islands</option>
<option value="AF">Afghanistan</option>
<option value="AL">Albania</option>
<option value="DZ">Algeria</option>
</select>
</form>
</div>

CSS

.register_account
{
    background: #0023C4;
    width:62%;
	padding:1.5%;
}

.register_account form select{
	width:100%;
	font-size:0.8em;
	color:#000;
	padding:8px;
	margin:5px 0;
	background: none;
	border: 1px solid #fff !important;
}

.register_account option[value=null]
{
    color:yellow;
}