Comment by adrian_b

This is not a Bjarne issue.

The font is selected by the HTML/CSS of the ACM site, not by Bjarne.

There may be a bug in the CSS of the ACM site, but I think that it is more likely that anyone who does not see correctly formatted code on that page has forgotten to open the settings of their browsers and select appropriate default fonts for "serif", "sans serif" and "monospace".

As installed, most browsers very seldom have appropriate default fonts, you normally must choose them yourself.

In this case, whoever does not see a monospace font, which is mandatory for rendering the code on that page, because the indentation is done with spaces, which become too narrow if rendered with a proportional font, must have that proportional font set in their browser as a default monospace font, so they should correct this.