Customzing the Login Page

Hi All,
We are creating a simple clock in clock out system through wordpress locally,
The users have a 4 digit code as their username and password.
There will be two touch screen devices online that they use, and for the clock in system to work they need to log into their user account and THEN clock in.

Any chance of adjusting/customizing the login page of wordpress to show just the numeric keypad on IOS/Android Devices?