It is perfectly legal in HTML to not quote attributes, and the FONT-tag is also a perfectly legal HTML-tag. Purely presentational markup (like the FONT-tag) is

It is perfectly legal in HTML to not quote attributes, and the FONT-tag is also a perfectly legal HTML-tag. Purely presentational markup (like the FONT-tag) is legal and not a problem. It is only a problem (e.g. for accessibility) when information is conveyed only through presentational markup, or when semantic markup are misused for presentation (eg tables for layout or blockquote for margins). But validation cannot detect these kinds of problems (because it requires an understanding of the meaning of the document), so validation is pretty useless to determine if the HTML is "good" or "bad". Validation is highly overrated as a means of determining the standards-compliance of a web-site.