Added examples and definition - CSS (#20066)

* Added examples and definition - CSS

- added two examples with the most used values
- added definition

* Added resources to Graceful Degradation - CSS

Added links to multiple articles / post / explanations / tools to help coders understand the concept

* changed triple backtick to single

* fixed https link

- had to fix one link to point to the https site
- removed one link because it doesn't match with the guide provided by FCC

* Add a space between class name and curly brace

guide/english/css/graceful-degradation/index.md

@@ -18,3 +18,15 @@ title: Graceful Degradation
  
  A simple example is the use of 24-bit alpha-transparent PNGs. Those images can be displayed on modern browsers without problems. IE5.5 and IE6 would show the image, but transparency effects would fail (it can be made to work if necessary). Older browsers that do not support PNG would show alt text or an empty space.
 
+
+### Resources
+
+[How can polyfills be used as a fallback for older browsers](https://developer.mozilla.org/en-US/docs/Glossary/Polyfill)
+
+[What is polyfill](https://remysharp.com/2010/10/08/what-is-a-polyfill)
+
+[Online HTML beautifier](https://www.10bestdesign.com/dirtymarkup/)
+
+[W3C CSS validator](https://jigsaw.w3.org/css-validator/)
+
+[MDN - Graceful degradation](https://developer.mozilla.org/en-US/docs/Glossary/Graceful_degradation)

guide/english/css/pointer-events/index.md

@@ -3,9 +3,27 @@ title: Pointer Events
 ---
 ## Pointer Events
 
-This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/css/using-css-transitions/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+This property specifies how your mouse reacts when you hover over any element on a page.
 
-<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+### Example
+
+```css
+
+.example {
+  pointer-events: auto; 
+  /*this will use the default look set by the browser agent*/
+}
+
+.example {
+  pointer-events: none; 
+  /*this will use the regular mouse look when hovered over the element*/
+}
+
+```
+
+### Other acceptable values
+
+Other values could be: `initial`, and `inherit`
 
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