Spacing is the hit rule. 60 px targets with ≥ 24 px clear between them, so every centre is ≥ 84 px from the next (P-08). Inside a platter row, where the next row's control is only 20 px away, a 60 px button takes Steam's free ::before as an 80 px extender.

Gamepad focus adds white .28, a spot in the upper third and the button's own arc ×1.5: ≥ 40 L over rest (P-14). Laser hover adds .08 and a light at the pointer, under the label (P-10). Glyph badges show only while the controller drives (P-26).