Rollup merge of #34921 - GuillaumeGomez:css_fix, r=steveklabnik
Rollup merge of #34921 - GuillaumeGomez:css_fix, r=steveklabnik

[CSS] Fix unwanted top margin for toggle wrapper

Fixes top margin.

Before:

![before](https://cloud.githubusercontent.com/assets/3050060/16950833/72b2b956-4dc2-11e6-9d27-24507871b5a8.png)

After (check "A view into a single entry in map" toggle wrapper more precisely):

![after](https://cloud.githubusercontent.com/assets/3050060/16950839/7835c6fc-4dc2-11e6-901a-ae8c4191baca.png)

r? @steveklabnik

GBGamer/rust,aidancully/rust,GBGamer/rust,aidancully/rust,graydon/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,graydon/rust