Are you editing the .css files? If so then that's your problem - you need to edit the LESS files:
Ohhh, I have read several times that it´s made with less... Thanks.
It works well in previous vertion (v1.13.0)
Ok. I found it does not work for administrator, but works well for regular users.
regular users, there is a invitation button (that green one)
administrator: no invitation button (that green one)
This is due to the invitation numbers settings in ACP. Looks the admin's invitation numbers is limited, which is identical with regular users. But it should be not limited. It looks like a bug.
Now everytime when I want to invite someone to register, I go the ACP to set the "max number one can invite" to be 0 (disable), then I invite, then I enable it (setting it to be 1)...
Can we fix it? It looks not a serious bug.
Thanks for reporting fixed in https://github.com/NodeBB/NodeBB/commit/8f4b99a41c6496cbdaaf489f16ecbe261d6c4a79
Ignore previous commit, this should fix it properly https://github.com/NodeBB/NodeBB/commit/071506eb7dc99e057b5bfde4543eadb75174a19a