case add : login
Merge pull request #14 from karynsong/dev

垂直居中
case background add
Merge branch 'dev' of github.com:techird/baidu-fe-site into dev
Merge pull request #15 from pengzhanlee/dev

case add
nav widget
Merge branch 'dev' of https://github.com/techird/baidu-fe-site into dev