Try a before pseudo-element

sitefiles/sig.css

@@ -93,9 +93,12 @@ body{
             z-index:0;
         }
 
+        .contentBody .contentWrapper .date:before{
+            background: linear-gradient(0deg,rgba(255, 255, 255, .06) 0%, rgba(255, 255, 255, .06) 90%, rgba(255, 255, 255, .9) 100%);
+        }
+
         .contentBody .contentWrapper .date{
             font-size:0.75em;
-            background: linear-gradient(0deg,rgba(255, 255, 255, .06) 0%, rgba(255, 255, 255, .06) 90%, rgba(255, 255, 255, .9) 100%);
             margin: 0px 4px 0px 4px;
             min-width:98vw;
             z-index:0;