JSFiddle - React, Tailwind, and code Playground

HTML

<div id="content">
    image<br>image<br>image<br>image<br>image<br>image<br>image<br>image<br>image<br>image<br>
    <div id="hoverbar">
        details
    </div>
</div>

CSS

*{
    margin:0;
    padding:0;
}
#content{
    height:100%;
    width:100%;
    background-color: #CCCCCC;
    padding:0;
    margin:0;
    position:absolute;
}
#hoverbar{
    height:100%;
    width:100%;
    background-color: #666;
    position:absolute;
    top:0;
    left:0;
    visibility:hidden;
    
}
#content:hover > #hoverbar{
    visibility:visible;
}