YA fantasy. Girl can create reality with her mind. Encounters powerful ruler. Finds underground area with lights permanently on. Battle with fire in the air burning tall people. Read '95-'05.

[Jamdat]

I remember reading this YA fiction book a long time ago, sometime between '95-'05 probably. Not sure if it was newly published or an older book I got from a library.

Points I remember:
- A girl, possibly noble, has started to be able to create reality on her own (objects and small things). She is transported or pulled to a place unfamiliar to her. She might be there with a companion/friend. They find that the male ruler of this place is powerful and has the same reality creating skill she does. His name might start with an 'H'.
- They get thrown in jail at one point, but escape somehow.
- She seeks people to fight against this ruler and discovers an underground construction, man made, with electric lights permanently on. When she asks a person inside, he says that the ruler must have forgotten about this place while the lights were on and so it stays this way since if the ruler is not thinking about you, you don't exist.
- There is a big feast where the girl is invited and gets a nice dress. Sits near the ruler.
- There is a fight between the ruler and the girl at some point. During the fight, the air is filled with a fiery cloud which descends on the crowd. The tallest people start getting hair singed and cry out. The girl creates rain to put out the fire.

Important plot point below in spoiler.
(view spoiler)[
- The girl and the ruler meet and the ruler turns out to be the girl in the future. She has become a man and sent out a call for successors or co-rulers and did not know that the request would travel through time as well and reach his past self.
(hide spoiler)]

Many thanks for any help finding the title!

[Tab]

Do you remember the cover?
Part of a series?
Time period story takes place?
Were there other fantasy elements, like dragons, witches, elves, etc?

[Jamdat]

Tab wrote: "Do you remember the cover?
Part of a series?
Time period story takes place?
Were there other fantasy elements, like dragons, witches, elves, etc?"

Unfortunately, I don't remember the cover and I'm not sure if was part of a series. I don't think so as I would likely have been motivated to read the others and would remember more.

I feel like this story takes place in a world that is sort of but not quite our own (e.g. there are electric lights, but they live in a castle). It's definitely not modern age, but it's not middle ages either.

I think the only fantastical element is this reality creating ability. I don't remember any dragons or the like but can't really remember enough to say for certain.