Flat casually put together in a bright way (8)
I believe the answer is:
limpidly
'in a bright way' is the definition.
I can't tell whether this definition defines the answer.
'flat casually put together' is the wordplay.
'flat' becomes 'limp' (I can't justify this - if you can you should give a lot more credence to this answer).
'casually' becomes 'idly' (I've seen this in another clue).
'put together' says to put letters next to each other.
'limp'+'idly'='LIMPIDLY'
Can you help me to learn more?
(Other definitions for limpidly that I've seen before include "calmly" , "clearly" .)