Notice the verb tense — the light “shines,” present and ongoing, not “shone once” or “will eventually shine.” This isn't a light that flickered briefly against the dark long ago; it's presented as a continuous, current fact. John names this light directly a few verses later: “the true light that gives light to everyone was coming into the world” (v9) — meaning this isn't a metaphor floating free of a person. It's Jesus, arriving into the actual dark of a particular time and place. And the text doesn't say the darkness has been eliminated — it says the darkness “has not overcome it.” Darkness is still real, still active, still something you genuinely encounter. But it has not won, and it structurally cannot, not because darkness stopped trying, but because of who this particular light is.