We want blank.page to be available everywhere. That's why we added support for writing offline. This is the kind of feature you don't need until you're on a 12-hour flight with Wi-Fi that just doesn't work. Only then does it become urgent.
Now, when you go offline, you'll see a small badge in the upper-left corner. You can keep writing as usual. Heck, you can even close the tab and open it later. Your changes will be saved locally — as they always are.
Go ahead, go offline, and give it a try!