.checked.featured{
   // ...
}

参考：http://www.w3.org/TR/selectors/#class-html

例

div{margin:1em;padding:1em;}

.checked{color:green;}
.featured{border:1px solid #ddd;}

.checked.featured{
       font-weight:bold;
    }

<div class="checked">element with checked class</div>
<div class="featured">element with featured class</div>
<div class="featured checked">element with both checked and featured classes</div>