Tweak responsive event form style

### desktop

![2013-01-26-224843_533x463_scrot](https://f.cloud.github.com/assets/35768/99836/c7bdc556-67c7-11e2-9eb3-540d19675c3a.png)

### < 979px

![2013-01-26-224831_414x547_scrot](https://f.cloud.github.com/assets/35768/99837/e2ef4070-67c7-11e2-8197-aa56d03687a4.png)

### < 767px

![2013-01-26-224815_527x537_scrot](https://f.cloud.github.com/assets/35768/99839/f5f24000-67c7-11e2-9d34-348f61d6d40a.png)

### < 480px

![2013-01-26-224742_286x638_scrot](https://f.cloud.github.com/assets/35768/99840/febdf3b4-67c7-11e2-908f-451d17608523.png)