CSS Styles: overflow on pre element

Hello! I was just hoping to make it easier for people to read the course website notes on mobile devices.

On mobile devices, long code snippets within the pre elements have overflow:
```html

insert_long_piece_of_code

As a result, the code snippets & page look like this on mobile:

The issue identifies long code snippets in pre elements as overflowing on mobile, but does not name a stylesheet or test. Locate the CSS affecting the course website's pre and code elements, reproduce the narrow-screen layout, and verify that long snippets no longer overflow while remaining readable.

Written by the indexing model from the issue text.