src/vs/workbench/browser/parts/sidebar/sidebarPart.ts/SidebarPart/updateStyles
class SidebarPart:	override updateStyles(): void {
		super.updateStyles();

		// Part container
		const container = assertIsDefined(this.getContainer());

		container.style.backgroundColor = this.getColor(SIDE_BAR_BACKGROUND) || '';
		container.style.color = this.getColor(SIDE_BAR_FOREGROUND) || '';

		const borderColor = this.getColor(SIDE_BAR_BORDER) || this.getColor(contrastBorder);
		const isPositionLeft = this.layoutService.getSideBarPosition() === SideBarPosition.LEFT;
		container.style.borderRightWidth = borderColor && isPositionLeft ? '1px' : '';
		container.style.borderRightStyle = borderColor && isPositionLeft ? 'solid' : '';
		container.style.borderRightColor = isPositionLeft ? borderColor || '' : '';
		container.style.borderLeftWidth = borderColor && !isPositionLeft ? '1px' : '';
		container.style.borderLeftStyle = borderColor && !isPositionLeft ? 'solid' : '';
		container.style.borderLeftColor = !isPositionLeft ? borderColor || '' : '';
		container.style.outlineColor = this.getColor(SIDE_BAR_DRAG_AND_DROP_BACKGROUND) ?? '';
	}