Stripping slashes

Looks like with the new 4.3 customizer there’s an issue where using slashes in the content rule get stripped out. So…

content: '\35';

becomes

content: '35';

Which is unusable for this purpose. Love this plugin and recommend it often. Hope there’s a relatively easy fix. Thanks!

https://ww.wp.xz.cn/plugins/modular-custom-css/