Preparing Hong Kong to resist invasion in 1997

What investments after the Falklands War could prepare Hong Kong to resist invasion in 1997?

Roughly three weeks of resistance is the objective, using mines, bunkers, civilian protection, local training, and more Gurkhas.

The proposed objective is about three weeks of resistance, giving international diplomatic and economic pressure time to develop. Alex would invest in minefields, bunkers, civilian protection, and preparations for fighting in a dense city. He also proposes reinforcing the Gurkhas and recruiting and training local defenders. The aim is to prolong resistance against a much larger opponent until outside pressure develops.