Which complexions is shade -03 Illuminator intended for?

It is intended for light to fair skin tones and is described as light and cool-toned.

Is this a single contour powder or a two-shade compact?

It is a two-shade pressed-powder contour compact.

Does it create a soft contour or a bold, high-impact look?

It is designed for soft, natural-looking definition. The color can be layered gradually when you want a more defined result.

How should I apply and blend this contour powder?

After sunscreen and foundation, lightly sweep a small amount of loose powder along the face line to reduce clumping from oiliness or base makeup. Use a contour brush to apply a small amount where you want definition, blend gently, and build gradually.