A close x on the tuning lab. It runs the same toggle as the T key and the collapsed chip, so all three ways of closing the panel agree about the cursor.
The tuning lab has a new look: a near-black card with a 16px radius and a hairline border, the kit accent on the active control, and pill slider tracks with a flat accent fill. Key chips are pure white on their plate so the legend stays readable against it.
Text in the panel has a hierarchy now. The stylesheet declared no font size at all and rode the engine default; it sets 16/14/13 with real line heights.
A dial dragged to the bottom of its range still reads as a pill instead of an empty track, and the track lights up under the cursor.
The tuning lab was drawing with almost none of its intended styling. Its stylesheet carried six border shorthands with a border-style in them, which is a parse error in the engine's CSS that throws away the entire sheet. Those are gone, along with two box-shadows, an inset shorthand and a gradient fill the engine does not support.
The dials are still one long list. Grouping them behind Engine, Suspension, Tires and Brakes tabs needs real tab state, so it is a later build.