Post Detail

Summary: * small site wide style tweaks

Test Plan:
### Global Styles and Small Tweaks

* just make sure nothing is broken
* review styles and feedback as needed

### Post Detail

* load the home page
* click post the first post title
* confirm it directs to post-detail.html
* check post-detail content and styles
* resize browser for responsive views

### Post Detail Sidebar

* check styles and content
* resize browser for responsive views

TODO:
* implement light box for thumbnail images

Reviewers: shadowhand, seth

Subscribers: sebm90, digitalafrican, eyedol, lkamau, srutto, dkobia, rjmackay

Differential Revision: https://phabricator.ushahidi.com/D267