In plotly_express how to highlight the trace on hover

In a simple Dash/Plotly Express app I know now how to disable the per-data-point hover information.

How can I instead highlight the whole trace I’m hovering over? (E.g. making it thicker or similar.) This would be super helpful when presenting data to others with Dash. (When you say e.g. “Let’s look at the curve for elderly people.” you could highlight easily on screen the trace with the data for elderly people, while keeping the other traces still visible in the background.)