I'm playing on the browser, and for privacy/security reasons I generally have my data deleted on most websites after shutting down my PC.

I noticed there's an export function, which I have used, but how do I import the save?

It wasn’t obvious to me either, but in the main menu it’s in the settings menu when you click the gear icon in the upper left. The option doesn’t show up while you’re playing the game, it has to be from the main menu.

Is that on the website or download version?

Because this is what the gear icon in the main menu shows me.

Sorry, I was looking at the download version, you’re right that it doesn’t show up in the web version.