对JS开发人员来说，了解CSS有多重要？

I am good in Javascript and angular stuff and found it very much interesting but bad in CSS and designing a layout of the page.I can't simply design a page.I dont found interest in CSS stuff.I want to be a SPA developer but is it possible without mastering CSS?Whenever i got a task related to Javascript,i have to face css/stylesheets.How much its important for a JS developer to know CSS?I am good in Javascript and angular stuff and f