Add background pattern to showcase

static/css/style.less

@@ -1269,6 +1269,11 @@ section#showcase {
     position: relative;
     flex-direction: column;
     min-height: 40vh;
+    background-image:  url("data:image/svg+xml,%3Csvg width='6' height='6' viewBox='0 0 6 6' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='%23000000' fill-opacity='0.42' fill-rule='evenodd'%3E%3Cpath d='M5 0h1L0 6V5zM6 5v1H5z'/%3E%3C/g%3E%3C/svg%3E");
+    // background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='4' height='4' viewBox='0 0 4 4'%3E%3Cpath fill='%23000000' fill-opacity='0.61' d='M1 3h1v1H1V3zm2-2h1v1H3V1z'%3E%3C/path%3E%3C/svg%3E");
+    &.gallery{
+        background-image: none;
+    }
     .textShadowedIntense();