src/vs/base/browser/ui/splitview/splitview.ts/SplitView/style
class SplitView:	style(styles: ISplitViewStyles): void {
		if (styles.separatorBorder.isTransparent()) {
			this.el.classList.remove('separator-border');
			this.el.style.removeProperty('--separator-border');
		} else {
			this.el.classList.add('separator-border');
			this.el.style.setProperty('--separator-border', styles.separatorBorder.toString());
		}
	}