Now we want to change a variable value inside a media query.
Here, we first declare a new local variable named --fontsize for the .container
class.We set its value to 25 pixels.
Then we use it in the .container
class further down.Then, we create a @media
rule that says "When the browser's width is 450px or wider,
change the --fontsize variable value of the .container class to 50px."