Widget Goes out of Place

this section (from Twente Twelve 1.0) seems to have gone lost:

.template-front-page .widget-area .widget:nth-child(even),
	.template-front-page.two-sidebars .widget-area .front-widgets + .front-widgets {
		float: right;
		width: 39.0625%;
		margin: 0 0 24px;
		margin: 0 0 1.714285714rem;
	}

add it back into style.css, after these styles:

.template-front-page .widget-area .widget,
	.template-front-page.two-sidebars .widget-area .front-widgets {
		float: left;
		width: 51.875%;
		margin-bottom: 24px;
		margin-bottom: 1.714285714rem;
	}