MDN is a better source of information wrt W3Schools

Author: mcagl

en/css/README.md

@@ -70,7 +70,8 @@ Time to write some CSS! Open up the `blog/static/css/blog.css` file in your code
 We won't be going too deep into customizing and learning about CSS here. There is a recommendation for a free CSS course at the end of this page if you would like to learn more.
 
 But let's do at least a little. Maybe we could change the color of our headers?
-To understand colors, computers use special codes. These codes start with `#` followed by 6 letters (A–F) and numbers (0–9). For example, the code for blue is `#0000FF`. You can find the color codes for many colors here: http://www.colorpicker.com/. You may also use [predefined colors](http://www.w3schools.com/colors/colors_names.asp), such as `red` and `green`.
+To understand colors, computers use special codes. These codes start with `#` followed by 6 letters (A–F) and numbers (0–9). For example, the code for blue is `#0000FF`. You can find the color codes for many colors here: http://www.colorpicker.com/. You may also use predefined [named colors](https://developer.mozilla.org/en-US/docs/Web/CSS/named-color), such as `red` and `green`.
+
 
 In your `blog/static/css/blog.css` file you should add the following code:
 
@@ -91,8 +92,7 @@ We also identify elements by the attribute `class` or the attribute `id`. Class
 <a href="https://en.wikipedia.org/wiki/Django" class="external_link" id="link_to_wiki_page">
 ```
 
-You can read more about [CSS Selectors at w3schools](http://www.w3schools.com/cssref/css_selectors.asp).
-
+You can read more about [CSS Selectors at MDN](https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_selectors).
 We also need to tell our HTML template that we added some CSS. Open the `blog/templates/blog/post_list.html` file in the code editor and add this line at the very beginning of it:
 
 {% filename %}blog/templates/blog/post_list.html{% endfilename %}