JSFiddle - React, Tailwind, and code Playground

HTML

<h3>My Title <a href="#">link</a></h3>

CSS

h3 {
    display:block;
    margin:20px auto;
    padding:6px;
    width:85%;
    text-align:left;
    font: 21px 'lucida sans'; color:#444; 
    border-bottom:#ccc 1px solid;
}
h3 a{
    margin:0; padding:8px 4px 0 0;
    display:inline;
    float:right;
    width:auto;
    text-decoration:none;
    font: 14px 'lucida sans';   
}

h3 a:before{ 
    content: '+'; 
    margin:0; 
    padding: 4px;
    position: absolute;
    left: -15px;
    top: 3px;
}

h3 a:hover { position: relative; }
h3 a:hover:after{ content:""; position: absolute; height: 1px;  
    right: 4px; /* depends of the right padding */
    left: 0; /* depends of the left padding */
    background-color: blue; /* depends of the link color */
    top: 23px; /* depends of the overall line-height */ }