Small HTML fix for Operation Guide

Fix "align".

Currently:

![bug](https://cloud.githubusercontent.com/assets/1506457/2811347/b15892bc-ce16-11e3-99b4-0841b2cc9629.png)

With this PR:

![fix](https://cloud.githubusercontent.com/assets/1506457/2811349/c04ae27a-ce16-11e3-9d26-1a39c0cab2e9.png)