I came across the following sentence the other day, and my wife who is a native German speaker from Austria insists it is correct. But by the rules I have been taught it is wrong. Can someone explain why wie should be used here instead of als?
Seine Hose ist nicht so bunt wie die Jacke.
The rules I am going by are: wie when comparing things that are the same, and als when different. So my interpretation is that the two items are different in that one is not as colourful as the other.