src/vs/workbench/browser/parts/views/viewPaneContainer.ts/ViewPaneDropOverlay/updateStyles
class ViewPaneDropOverlay:	protected override updateStyles(): void {

		// Overlay drop background
		this.overlay.style.backgroundColor = this.getColor(this.location === ViewContainerLocation.Panel ? PANEL_SECTION_DRAG_AND_DROP_BACKGROUND : SIDE_BAR_DRAG_AND_DROP_BACKGROUND) || '';

		// Overlay contrast border (if any)
		const activeContrastBorderColor = this.getColor(activeContrastBorder);
		this.overlay.style.outlineColor = activeContrastBorderColor || '';
		this.overlay.style.outlineOffset = activeContrastBorderColor ? '-2px' : '';
		this.overlay.style.outlineStyle = activeContrastBorderColor ? 'dashed' : '';
		this.overlay.style.outlineWidth = activeContrastBorderColor ? '2px' : '';

		this.overlay.style.borderColor = activeContrastBorderColor || '';
		this.overlay.style.borderStyle = 'solid' || '';
		this.overlay.style.borderWidth = '0px';
	}