> JavaScript polyfills to support new baseline HTML/CSS features are a necessity for sustainable future-and-past-proof development in the modern Web ecosystem
I'd wager that most people who disable Javascript are using a modern browser with a good blocklist/whitelist system, e.g. Firefox with NoScript.
For instance, if your website needs Flexbox, your CSS will work even on Firefox 25 with NoScript. Flexbox won't work on IE8 with JS off, but that's honestly OK. Progressive enhancement will still allow the visitor to read the content and interact with the page, the only issue is that the elements won't be positioned as intended by the designer. If you're willing to invest more time to support even IE8 with JS off, you could use Sass to more or less replicate Flexbox with floats etc.
Usually, until a CSS/HTML feature is supported by at least two major browsers, it's not a good idea to use it in production.
I'd wager that most people who disable Javascript are using a modern browser with a good blocklist/whitelist system, e.g. Firefox with NoScript.
For instance, if your website needs Flexbox, your CSS will work even on Firefox 25 with NoScript. Flexbox won't work on IE8 with JS off, but that's honestly OK. Progressive enhancement will still allow the visitor to read the content and interact with the page, the only issue is that the elements won't be positioned as intended by the designer. If you're willing to invest more time to support even IE8 with JS off, you could use Sass to more or less replicate Flexbox with floats etc.
Usually, until a CSS/HTML feature is supported by at least two major browsers, it's not a good idea to use it in production.