Create a `no-css-mode`

[pdelfino]

Nyxt already offers commands that help to provide a low-bandwidth navigation, such as:

• no-image;
• no-script; and,
• no-webgl.

no-css-mode is another alternative. It could also be handy for front-end developers (to do some tests).

I have pitched the idea to @jmercouris. He liked it but he was not sure about how to implement it. He speculated if there would be some WebKit API to disable CSS.

[pdelfino]

Today, @jmercouris suggested using a variation of blocker-mode. It would be enough to block .css files from loading. However, it would not work for in-line css (which tends to be the minority of CSS occurrence).

[jmercouris]

Which is /probably/ the minority. We don't have data to show that- yet!

[aadcg]

I don't think this is Nyxt's responsibility, but that of the renderer. If the renderer provides such an option, then it's trivial to implement it.