1. Visit a PR you can merge, like https://github.com/sindresorhus/refined-github/pull/4136 2. Resize the window to 900px of width 3. Notice the overflow: <img width="684" alt="Screen Shot 3" src="https://user-images.githubusercontent.com/1402241/112183541-f9288d00-8bc3-11eb-95b9-0975d1d50a4a.png"> This is due to https://github.com/sindresorhus/refined-github/pull/4070 Unfortunately we want the `content-box` to be _72ch_ the `border-box` to be _max-width: 100%_