When i change the hexidecimal code to Blue and when i refresh the browser it doesn`t work?

Actually I found you had to click. file>save. to save the css changes and then refreshing the preview did show the updated colour

I had the same issue.

The teacher had used background color: #XXXXXX;

However you use blue you just need to do color: blue;

I.e. don't include a hashtag when just using a color.

Hope this helps!

command + s on mac saves the worksheet, too. then refresh the webpage and your changes should show up.

If you have attempted to fix your code and still no luck, here is the line of code that is correct. (Be sure to save code before refreshing)

background-color: blue;

Feel free to mess around with it and make it more than just a blue color!

Are you saving the css sheet before refreshing? Do you have an issue with your code? There's multiple different reasons why its not working but we are not able to tell unless we get some clarification or a snippet of your code to try and find the issue