JSFiddle - React, Tailwind, and code Playground

HTML

<input type='text' placeholder='Test' />

CSS

::-webkit-input-placeholder::first-letter {
	color: purple;	
}


:-moz-placeholder::first-letter { /* Firefox 18- */
   color: red;  
}

::-moz-placeholder::first-letter {  /* Firefox 19+ */
   color: red;  
}

:-ms-input-placeholder::first-letter {  
   color: red;  
}