Apparently it's only a font problem with the remote website and has nothing to do with the locale configuration on your system.
Additionally, the browser has its own locale settings and the locale configuration does not affect the web rendering mechanism (maybe the browser UI but nothing else).
To show the system locale, simply run locale
The following actions were recommended on Qt support forum:
In Qt Creator, add remote Linux device in Options -> Devices. Set its address as localhost and user as root. Create a pair of authentication keys and paste public key to /root/.ssh/authorized_keys.
Then clone Desktop kit in Options -> Kits and set the device for new kit to the device you've created ...
It is possible to install qtcreator version 2.5.2-0ubuntu1 from Ubuntu 12.10 (Quantal Quetzal) which is EOL (will not get security updates for its packages).
But it will not work because of version problems of corresponding qt4-qmake.
So I'll suggest to use modern Qt Creator from your Ubuntu version to build Qt projects.
To setup it for Qt4 your need to ...
You have an incomplete installation of Qt Creator, but you can also install Qt Creator (qtcreator) from the default Ubuntu repositories instead of manually downloading Qt Creator and installing it. In all currently supported versions of Ubuntu open the terminal and type:
sudo apt install qtcreator cmake g++ git qt5-default
After you have installed qt5-...