Group figure-card styles together

This way rules are a bit easier to follow.

app/assets/stylesheets/layout.scss

@@ -2840,21 +2840,6 @@ table {
     }
   }
 
-  .figure-card {
-
-    figcaption {
-      z-index: 3;
-    }
-
-    .gradient {
-      background: linear-gradient(to bottom, rgba(0, 0, 0, 0) 0%, rgba(0, 0, 0, 0.01) 1%, rgba(0, 0, 0, 1) 100%);
-      height: 100%;
-      position: absolute;
-      width: 100%;
-      z-index: 2;
-    }
-  }
-
   figure img {
     height: 100%;
     width: 100%;
@@ -2906,6 +2891,14 @@ table {
     }
   }
 
+  .gradient {
+    background: linear-gradient(to bottom, rgba(0, 0, 0, 0) 0%, rgba(0, 0, 0, 0.01) 1%, rgba(0, 0, 0, 1) 100%);
+    height: 100%;
+    position: absolute;
+    width: 100%;
+    z-index: 2;
+  }
+
   img {
     height: 100%;
     width: 100%;
@@ -2920,6 +2913,7 @@ table {
     padding: $line-height / 4 $line-height / 2;
     position: absolute;
     width: 100%;
+    z-index: 3;
 
     h3,
     .title {