src/vs/editor/contrib/peekView/browser/peekView.ts/PeekViewWidget/style
class PeekViewWidget:	override style(styles: IPeekViewStyles): void {
		let options = <IPeekViewOptions>this.options;
		if (styles.headerBackgroundColor) {
			options.headerBackgroundColor = styles.headerBackgroundColor;
		}
		if (styles.primaryHeadingColor) {
			options.primaryHeadingColor = styles.primaryHeadingColor;
		}
		if (styles.secondaryHeadingColor) {
			options.secondaryHeadingColor = styles.secondaryHeadingColor;
		}
		super.style(styles);
	}