How many GB does Hearthstone use?

How many GB does Hearthstone use?
Windows

Minimum Requirements

Storage

3 GB available HD space

Internet
Broadband Internet connection

Input
Keyboard and mouse, or touchscreen

Resolution
1024 x 768 minimum display resolution

Windows
Minimum Requirements
Storage 3 GB available HD space
Internet Broadband Internet connection
Input Keyboard and mouse, or touchscreen
Resolution 1024 x 768 minimum display resolution