Where is my div class for single posts?

I feel like such a dummy, but all I can find is this in my single.php:

<div id=”primary” class=”content-area”>
<div id=”content” class=”site-content” role=”main”>

And I’m trying to accomplish a link image fade:

.single-post a {
opacity: 1.0; !important;
transition: opacity .2s ease-in-out; !important;
-moz-transition: opacity .2s ease-in-out; !important;
-webkit-transition: opacity .2s ease-in-out; !important;
}
.single-post a:hover {
opacity: 0.6; !important;
transition: opacity .2s ease-in-out; !important;
-moz-transition: opacity .2s ease-in-out; !important;
-webkit-transition: opacity .2s ease-in-out; !important;
}

The strong text is the div class I’m missing – how can I fix this?