How can you build a mobile responsive content (blog post) editor?

So first I'm gonna declare that I meant editor as the editor for editing blog posts or documents, not something that you use to build mobile responsive websites like wix, weebly etc.

So how can I make this, for a website? I found out most of the service out there have their app included with a mobile responsive editor like Google docs, Evernote. But I haven't found a website that got a usable editor on mobile. Let's make CKEditor as an example, it isn't comfortable to select a text, then scroll to the top, format the text, then scroll back down, while also the site will be jumping around and the keyboard will show/hide accidentally.

So how can you solve this? The first idea I came up with is copying what Evernote do, make a little toolbar that gets you three section for formatting, styling, and alignment but it looks like since we're using on website and not apps, you can't change the keyboard (or there's way you can achieve it on website but I didn't find it).

With this one failed, I have no idea how to build a content editor on websites while it can work smoothly on mobile phones.

Who can help me out?