mediawiki-skins-Vector/resources/skins.vector.styles/layouts/toc/pinned.less

.vector-column-start .vector-sticky-pinned-container {
	// Aligns the text of the sidebar TOC with the main menu.
	// The negative margins must be applied here, because .vector-sticky-pinned-container has
	// contain: paint, which has an effect similar to 'overflow: hidden', and will prevent elements
	// inside of the panel from being rendered outside of its bounding box, even when they would
	// be positioned there using absolute positioning, negative margin, transforms, etc.
	margin-left: -@toc-list-item-padding-start;
}