Drill: Sidebar nav: collapsible sidebar with 3 sections, badges, icons+labels, collapsed tooltips, active state. Must work at 240px and 48px widths.

Interpretation: Built as an underground mine-ventilation monitoring console (night shift): 3 sections (Monitor/Control/Records), 9 items, warning-count badges derived from the live dataset (warn sensors, fan faults, active alarms), collapse to 48px via button or [ key with tooltips carrying badge info. Dark Linear/Vercel ops aesthetic — Inter 450/650, JetBrains Mono tnum+zero, one blue accent scoped to the active-state semantic, shape-differentiated status glyphs for colorblind safety; mobile becomes a horizontal icon+label strip with corner count-dots.