src/vs/workbench/browser/parts/editor/tabsTitleControl.ts/makeTabBackgroundRule
		const makeTabBackgroundRule = (color: Color, colorDrag: Color, focused: boolean, active: boolean) => `
				.monaco-workbench .part.editor > .content:not(.dragged-over) .editor-group-container${focused ? '.active' : ':not(.active)'} > .title .tabs-container > .tab.sizing-shrink${active ? '.active' : ''}:not(.dragged):not(.sticky-compact) > .tab-label > .monaco-icon-label-container::after {
					background: linear-gradient(to left, ${color}, transparent);
				}

				.monaco-workbench .part.editor > .content.dragged-over .editor-group-container${focused ? '.active' : ':not(.active)'} > .title .tabs-container > .tab.sizing-shrink${active ? '.active' : ''}:not(.dragged):not(.sticky-compact) > .tab-label > .monaco-icon-label-container::after {
					background: linear-gradient(to left, ${colorDrag}, transparent);
				}
		`;