What tariffs has Trump introduced and why?

Trump launched sweeping new tariffs in his second term, but the US Supreme Court ruled his emergency IEEPA tariffs unlawful — prompting about $100bn in refunds — so his administration shifted to other trade laws to keep broad 10–12.5% levies in place on major partners.
The tariffs have pushed up prices for consumers and businesses (studies say roughly half the cost was passed on), helped fuel inflation, and hit poorer Americans hardest as everyday goods like toys, appliances and food became more expensive.
The measures have rattled global markets, prompted trade “re‑wiring” as allies seek alternatives, and drawn warnings from the IMF that the trade tensions are slowing world growth.