A:hover text on portfolio

Hi,

I'm trying to set an a:hover text on portfolio item, which I need to show only on mouse hover in https://www.magnetmarketing.it/portfolio/.

I set in the page content:

<div class="hover11 port">
<div>
<div class="figport"><a href="https://www.magnetmarketing.it/portfolio/brand-identity-b2b"><img src="https://www.magnetmarketing.it/wp-content/uploads/creazione-brand-identity-B2B.jpg" alt="Creazione brand identity nel settore B2B"></a></div>
<span>Creazione brand identity nel settore B2B</span>

</div>
<div>
<div class="figport"><a href="https://www.magnetmarketing.it/portfolio/programmatore-di-siti-web"><img src="https://www.magnetmarketing.it/wp-content/uploads/programmatore-siti-internet.jpg" alt="programmatore siti internet"></a></div>
<span>Pulizia codice programmazione sito web</span>

</div>
</div>

and for css:

.port {
	margin: 15px 15px 0;
	padding: 0;
}
.port:last-child {
	padding-bottom: 60px;
}
.port::after {
	content: '';
	clear: both;
	display: block;
}
.port div {
	position: relative;
	float: left;
	width: 300px;
	height: 200px;
	margin: 0 0 0 25px;
	padding: 0;
}
.port div:first-child {
	margin-left: 0;
}
.port div span {
    position: absolute;
    bottom: -20px;
    left: 0;
    z-index: -1;
    display: block;
    width: 300px;
    margin: 0;
    padding: 0;
    color: #444;
    font-size: 18px;
    text-decoration: none;
    text-align: center;
    -webkit-transition: .3s ease-in-out;
    transition: .3s ease-in-out;
    opacity: 0;
}

.figport {
	width: 300px;
	height: 200px;
	margin: 0;
	padding: 0;
	background: #fff;
	overflow: hidden;
}
.figport {
    display: block;
}
.figport:hover+span {
	bottom: -36px;
	opacity: 1;
	z-index: 1;
}

/* Opacity #1 */
.hover11 .figport img {
	opacity: 1;
	-webkit-transition: .3s ease-in-out;
	transition: .3s ease-in-out;
}
.hover11 .figport:hover img {
	opacity: .5;
}

but it's not working.
Can you help me please?