Change hint wording for adding CSS declaration blocks

grid/03-grid-layout-3/README.md

@@ -3,9 +3,9 @@
 Now that you've made your Holy Grail layout responsive, we are going to have some fun making it a bit more complicated and adding some features. You might find this to be a bit more challenging than you expected. You might even be tempted to use Flexbox. But for the sake of this practice assignment, try and see if you can figure out how to recreate this entire mockup using only Grid. Feel free to add in your own dummy content or styling too!
 
 ### Hints
+- For this exercise you will need to add some CSS declaration blocks to the style.css file. Look through the HTML to see what CSS classes you should use and remember you can use descendant selectors too
 - Take the layout one section at a time
 - You don't need to add or change anything to the HTML, but it will be helpful to look through the parent and child relationships between elements
-- You only need to add to the current CSS selectors
 - Just like with Flexbox, you can easily center an item by making it into a grid
 - Don't worry about the placeholder image element stretching when resizing the browser window. This will be covered in the Responsive lessons