Make Gmail Readable

I joined the Writing for Developers Book Club a few weeks ago.
This book club about the really great Writing for Developers is happening only by email. So I have a lot of emails to read.
But Gmail is not really great for this. It is displaying the emails on the whole width of the screen with a small font size and not a really good font.
I needed to improve the experience by making it more readable.

Using a chrome extension like Stylebot or Stylus we can add our own custom CSS. We configure a new stylesheet for the url https://mail.google.com:

Stylebot URL configuration

And then we just have to add our css code:

Stylebot css declaration

@import url('https://fonts.cdnfonts.com/css/open-sans');

.ii.gt {
  max-width: 680px;
  margin-left: auto;
  margin-right: auto;
  font-family: "Open Sans", Arial, serif;
}

.ii .a3s {
  font-family: "Open Sans";
  font-size: 16px;
  line-height: 27.6px;
}

Before

After