For example, executing file styles.css outputs:
styles.css: asssembler source text
whereas file bar.css outputs:
bar.css: ASCII text
Even better, is there a way to convert my file styles.css to ASCII text?
The results from file are not perfect; the command looks for predictable patterns to determine file types. The file command is guessing. Apparently it has identified some keywords for assembly. The character encoding is almost certainly ASCII or UTF-8 already. But it can be checked:
file -bi $filename
Both recode and iconv can change the encoding of a file.