Like crv383, I've done quite a bit of research on this subject also. There's a lot to know, it's quite involved.
Wheel Offset:
There are really 2 wheel offset numbers to pay attention to.
1) Is the offset the oem vehicle mfg designed the car for (for my 2014 crv the design is for offset of 50mm). That means king pin axis, scrub radius, wheel bearings, ball joints, etc. should meet standards set by the oem for wear and tear, if the offset of new wheels (for me) stays at 50mm.
(note: Some say the oem vehicle offset can vary a little (5mm) with no adverse affect, others say not to. There's really no definitive proof either way. The most important thing (if changing offset) is the obvious; the wheel and tire have to fit without rubbing fenders or hitting brake parts (especially full turns)).
2) The other offset number is the offset of the new wheel you want to use. If it's the same as oem design, no worries. But if it's not, it becomes confusing to understand it's relationship to the vehicle hub. The wheel offset is measured from the center of the wheel, not the vehicle hub. A positive offset means the wheel hub is farther out towards the face of the wheel. A negative offset means the wheel hub is farther in towards the car side of the wheel (again, measured from the center of the wheel - nothing to do with the car hub).
So what that means is when a wheel increases in offset, the hub of the wheel goes farther and farther out towards the face of the wheel (be the increase as less negative or more positive - both are increases in offset). That results in, on the vehicle, the wheel (and tire of course) being farther and farther into the wheel well (because the hub in the wheel is going farther and farther out towards the wheel face).
Just the opposite happens when you decrease offset. IE the tires and wheel go farther and farther out (from original).
It seems a** backwards doesn't it? The key is to remember the wheel offset isn't from the hub of the car, it's from the center of the wheel to the wheel hub (nothing on the vehicle is involved in this measurement).
Just sharing a bit I learned along this road... (I know, punny).
Cheers