well, during the night yes, obviously. but during the day many areas of a castle would have been fairly well lit by natural sunlight entering through windows or simply areas of the castle that didn't have a roof. Other, more secure places such as a dungeon or maybe a storage room for weapons or resources probably were fairly dark at all times of the day and you would have needed torches to illuminate them.
bricks or wood
You did not include any of the 'following'.
The Roman did not have any castles. Castles emerged after the end of Roman civilisation, during the Middle Ages.
Dark Ages and\or Medieval Ages
The Renaissance was not labeled the "dark ages". Renaissance means "rebrith" and it came AFTER the "dark ages or the middle ages."
in dark allies
Castles in the Middle Ages were used to keep out enemies.
No castles have been built since the middle ages
castles were important in the middle ages mainly in 1066 and onwards
the castles in the middle ages were made of stone not wood because wood would burn easily.
motte and bailey castles
they haven't and the middle ages is irrelevant
Fortified dwellings of the Middle Ages were castles and fortified manor houses. Not all dwellings were castles, however.
Castles in the early middle ages were motte and bailey castles- a motte was a large mound and a bailey was like a courtyard. These developed into the standard castle with strong stone walls etc.
Castles were developed in the middle ages because people thought that the kings and queens should live more wealthier than the peasant's. Therefore, they built castles.
Castles have a rather distinctive architecture, and were nearly all built in the Middle Ages. They were also politically and militarily important in the time.
There is a link below to a website on famous medieval castles.