What clothes should I wear in the northeast of MINUS 30 degrees?

At present, the lowest weather temperature in Northeast China is minus 20 degrees, and the average temperature is minus 10 degrees. The temperature difference between morning and evening is relatively large. They wear thick cotton trousers, thermal underwear, cotton shoes with velvet, hats, scarves and gloves, which are not much different from winter in other places. People living in the northeast of China have adapted to this kind of weather. When I was a child, the coldest time was MINUS 30 degrees. Children would wear cotton trousers made by adults, which were stuffed with thick cotton to keep warm.

I remember that when I was in college, it was about MINUS 20 degrees. On campus, I saw a girl wearing stockings and a down jacket shuttling through the crowd. Many passers-by looked at her in surprise, and we all felt trembling when we looked at her. Later, I learned that it may be a problem of regional differences. The north is dry and cold, and the room has heating, but the environment in which she grew up is relatively wet and cold, so she feels that the climate in the northeast is acceptable, not as cold as her home, and it may be a life in different regions.