Reduce padding, gaps, and font sizes across all components. Change html/body/root from min-height to fixed height with overflow hidden. Decrease app-frame padding from 18px to 12px and add grid-template-rows with overflow handling. Reduce brand lockup logo from 54px to 44px and adjust gaps throughout. Decrease button padding, surface padding, and card padding. Reduce body-grid sidebar from 290px to 250px.