JSFiddle - React, Tailwind, and code Playground

HTML

<select class="colorMeBlue noValue">
 <option value>--Select--</option>
 <option value="60">Salaried Employee</option>
 <option value="61">Trainee</option>
 <option value="62">Skilled Worker</option>    
</select>

CSS

select.colorMeBlue.noValue,
select.colorMeBlue option:first-child {
    color: blue;
}

select.colorMeBlue option:not(:first-child) {
    color: black;
}

JavaScript

$('select').on('change', function(){
    var $this = $(this);
    
    if (!$this.val()) {
        $this.addClass('noValue');
    } else {
        $this.removeClass('noValue');
    }
});