JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <div class="col-md-8 section span7 text-center">
        <div class="thumbnail">
            <img src="http://davidnaylor.org/temp/thunderbird-logo-200x200.png" alt="Site Pessoal">
            <div class="caption">
                <p><strong>Site</strong>
                </p>
                <p> <a href="#" class="btn btn-info gray gly_medium" id="site-imagens" title="Veja imagens">
                             <span class="glyphicon glyphicon-search"></span>
                        </a>
 <a href="#" class="btn btn-info gray gly_medium" title="Acesse o site">
                             <span class="glyphicon glyphicon-link"></span>
                        </a>

                </p>
            </div>
        </div>
        <div class="thumbnail">
            <img src="https://upload.wikimedia.org/wikipedia/en/7/71/Quebec_citadelles_200x200.png" alt="Video Site">
            <div class="caption">
                <p><strong>Video Content Site</strong>
                </p>
                <p> <a href="#" class="btn btn-info gray gly_medium" id="video-imagens" title="Veja Imagens">
                                    <span class="glyphicon glyphicon-search"></span>
                                </a>
 <a href="#" class="btn btn-info gray gly_medium" title="Acesse o site">
                                    <span class="glyphicon glyphicon-link"></span>
                                </a>

                </p>
            </div>
        </div>
        <div class="thumbnail">
            <img src="http://horoscopo.ego.globo.com/img/horoscopo.ego.globo.com/icones/signos/gemeos-g.png" alt="Video Site">
            <div class="caption">
                <p><strong>Video Site</strong>
                </p>
                <p> <a href="#" class="btn btn-info gray gly_medium" id="video-imagens" title="Veja Imagens">
                                    <span class="glyphicon glyphicon-search"></span>
                                </a>
 <a href="#" class="btn...

CSS

.thumbnail {
    display:inline-block
}
.caption {
    opacity:0;
    visibility: hidden;
    transition:opacity .5s;
    position:absolute;
    background-color:#fff;
    width:308px;
    margin-left:-5px
}
.thumbnail:hover .caption {
    visibility: visible;
    opacity:1;
    z-index:1
}