JSFiddle - React, Tailwind, and code Playground

HTML

<div id="triangle" />

CSS

#triangle {
    width: 0;
    height: 0;
    border-top: 20px solid transparent;
    border-bottom: 20px solid transparent;
    border-left: 40px solid red;
    -webkit-transition:all 1s ease-in;  
    -moz-transition:all 1s ease-in;  
    -o-transition:all 1s ease-in;  
    transition:all 1s ease-in;  
    
}

#triangle:hover{    
    -webkit-transform: rotate(90deg);
    -moz-transform: rotate(90deg);
    -o-transform: rotate(90deg);
    -ms-transform: rotate(90deg);    
}