The whole "only use five colours", of which one is black and three are meant for indication/states (error, warning, success) is an odd tip. Personally I always use a minimum of:
Primary
Variant
Dark A
Dark B
Light A
Light B
Success
Error
...and that's a minimum. Expecially important is the use of a primary and a variant colour as the primary palette.
The whole "only use five colours", of which one is black and three are meant for indication/states (error, warning, success) is an odd tip. Personally I always use a minimum of:
...and that's a minimum. Expecially important is the use of a primary and a variant colour as the primary palette.