On mobile (Safari), the lines in the code blocks have different font sizes. They also have different fonts. Some are like 3-4x the size of other lines. No idea what could be going wrong, but it does unfortunately make the code blocks difficult to follow along.
On desktop Iād suggest installing an extension that adds a toggle (they exist for Firefox and chrome at least): adding a toggle manually is a bit of a chore, especially if the css system you use does not build that in.