Moderate a style of painting (7)

I believe the answer is:

tempera

I'm a little stuck... Click here to teach me more about this clue!

'style of painting' is the definition.
'tempera' can be an answer for 'painting' (I've seen this before). I'm not certain of the 'style of' bit.

'moderate a' is the wordplay.
'moderate' becomes 'temper' (synonyms).
'temper'+'a'='TEMPERA'

Can you help me to learn more?

(Other definitions for tempera that I've seen before include "Method of drawing" , "vehicle" , "Artist's emulsion" , "may be useful to artist" , "Type of paint" .)

I've seen this clue in The Sun.

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