Design item as a container for light (6)
I believe the answer is:
ignite
'light' is the definition.
(thesaurus)
'design item as a container' is the wordplay.
'a container' says the answer is hidden in the clue.
'IGNITE' is hidden in the letters of 'design item as'.
'for' acts as a link.
(Other definitions for ignite that I've seen before include "Catch fire; provoke" , "Cause to start burning" , "Combust" , "Spark off" , "Detonate" .)