Codemoji uses only half the screen on Firefox for Android

![screenshot_2016-08-29-12-46-34](https://cloud.githubusercontent.com/assets/1616846/18049177/e2105b84-6de6-11e6-8229-da48becce1d7.png)

This means that some elements are half hidden, for example the message in this screenshot:
![screenshot_2016-08-29-12-47-33](https://cloud.githubusercontent.com/assets/1616846/18049179/e678244a-6de6-11e6-9f54-8915acfe9699.png)
