JSFiddle - React, Tailwind, and code Playground

HTML

<span class='inline-block decorated-link'>Ссылка в спане с {display: inline-block;} </span>
<br>
<br>
<a href='#' class='decorated-link'>Обычная ссылка</a>

CSS

.decorated-link {
    color: #337ab7;
    position: relative;
    text-decoration: none;
    cursor: pointer;
}

.decorated-link:hover {
    text-decoration: none;
    color: red;
}

.decorated-link:after {
    content: '';
    position: absolute;
    right: 0;
    left: 0;
    bottom: -8px;
    width: 100%;
    border-bottom: thin dashed rgba(51, 122, 181, 0.4);
}

.decorated-link:hover:after {
    border-color: rgba(255, 0, 0, 0.3);;
}

a.decorated-link:after {
    bottom: 0;
}

.inline-block {
    display: inline-block;
}