s/css class names in node/express

[dyspop]

correct me if i'm missing something but i can't seem to work around the fact that this framework uses invalid class names (which browsers don't care about when loaded as css) and node won't have this.

index.pug:
.six.actions.vertical.signup-email.6u$.12u$(xsmall)

but at express app run

Error: /Users/danielblack/code/dan.black/views/index.pug:139:47

 > 139|             .six.actions.vertical.signup-email.6u$.12u$(xsmall)
-------------------------------------------------------^

Class names must begin with "-", "_" or a letter.
   at makeError (/Users/danielblack/code/dan.black/node_modules/pug-error/index.js:32:13)
   at Lexer.error (/Users/danielblack/code/dan.black/node_modules/pug-lexer/index.js:58:15)
   at Lexer.className (/Users/danielblack/code/dan.black/node_modules/pug-lexer/index.js:416:12)
   at Lexer.callLexerFunction (/Users/danielblack/code/dan.black/node_modules/pug-lexer/index.js:1315:23)
   at Lexer.advance (/Users/danielblack/code/dan.black/node_modules/pug-lexer/index.js:1351:15)
   at Lexer.callLexerFunction (/Users/danielblack/code/dan.black/node_modules/pug-lexer/index.js:1315:23)
   at Lexer.getTokens (/Users/danielblack/code/dan.black/node_modules/pug-lexer/index.js:1371:12)
   at lex (/Users/danielblack/code/dan.black/node_modules/pug-lexer/index.js:12:42)
   at Object.load.string.lex (/Users/danielblack/code/dan.black/node_modules/pug/lib/index.js:93:27)
   at Function.loadString [as string] (/Users/danielblack/code/dan.black/node_modules/pug-load/index.js:44:24)

the important bit being: Class names must begin with "-", "_" or a letter.

[ajlkn]

Does it let you unicode escape class names (eg. .\36 u instead of 6u)?

[pogan]

Had the same problem. The workaround is quite trivial.
Instead of having:
.6u(class='12u(narrower)')
Do
div(class='6u 12u(narrower)')

And pug does not let unicode escape classes.