To these theme: CUPID, ZORKA, GROVE, DARNA, WOLVERINE, HANDMADE, MEGATRON, ACADEMIA when you have “Install Demo Data” completed but website not load success, please follow below instruction to fix this issue.
First, you should check Why “One Click Install Demo Data” not completed? to know more about variables on your server.
If everything done, after installation process finish, go to Theme Options then you click “Save All Changes” and click “Generate Less to CSS” button. Look like below: