When height is set to S, mode-select collapses to a row (mode button +
compact tools toggle side by side). M and L keep the vertical column
layout where each control gets its own full-width row. Driven by
data-size attribute set in JS so the switch is instant on click, not
reliant on a viewport media query. Removed the redundant max-height
landscape query.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>