I appreciate that while the CSB uses the word "overcome," in its footnotes it says "or grasp or comprehend or overtake; John 12:35"
The NIV uses the word "overcome" but its footnote says, "Or understood"
The NET translates it with the word "mastered" and its note is extensive (BTW - even though I don't use the NET as a translation very often, its notes are often very helpful and should be consulted regularly... and I think that's the case here...): "Or “comprehended it,” or “overcome it.” The verb κατέλαβεν (katelaben) is not easy to translate. “To seize” or “to grasp” is possible, but this also permits “to grasp with the mind” in the sense of “to comprehend” (esp. in the middle voice). This is probably another Johannine double meaning—one does not usually think of darkness as trying to “understand” light. For it to mean this, “darkness” must be understood as meaning “certain people,” or perhaps “humanity” at large, darkened in understanding. But in John’s usage, darkness is not normally used of people or a group of people. Rather it usually signifies the evil environment or ‘sphere’ in which people find themselves: “They loved darkness rather than light” (John 3:19). Those who follow Jesus do not walk in darkness (8:12). They are to walk while they have light, lest the darkness “overtake/overcome” them (12:35, same verb as here). For John, with his set of symbols and imagery, darkness is not something which seeks to “understand (comprehend)” the light, but represents the forces of evil which seek to “overcome (conquer)” it. The English verb “to master” may be used in both sorts of contexts, as “he mastered his lesson” and “he mastered his opponent.”
