Vector-Local/resources/skins.vector.styles/components/TableOfContents.less

@import '../../common/variables.less';

@sidebar-toc-fade-height: 30px;
@sidebar-toc-vertical-padding: 20px;
@sidebar-toc-right-padding: 12px;
// Sidebar TOC uses increased left padding and a negative left margin to achieve
// a 15px spacing without clipping the chevron icon
// https://phabricator.wikimedia.org/T312156#8095894
@sidebar-toc-left-padding: 15px + @icon-padding-md;
@toc-subsection-toggle-icon-size: 1.834em;

.mw-table-of-contents-container {
	// Needed for Grid-based layout
	align-self: start;
	height: 100%;
}

.vector-sticky-toc-container {
	// stylelint-disable-next-line plugin/no-unsupported-browser-features
	position: sticky;
	top: 0;

	@media ( min-width: @min-width-desktop ) {
		.vector-toc-not-collapsed & {
			// Default spacing separating the sidebar TOC from the main menu or viewport.
			// Need to use padding in order for the spacing to apply when sticky
			padding-top: 1.5em;
		}

		.vector-toc-not-collapsed @{selector-main-menu-closed} ~ .mw-table-of-contents-container & {
			// Needed to align TOC with bottom of title, 1.5em padding + 1.5em margin = 3em
			margin-top: 1.5em;
		}
	}
}

.sidebar-toc {
	max-height: 75vh;
	padding: @sidebar-toc-vertical-padding @sidebar-toc-right-padding @sidebar-toc-vertical-padding @sidebar-toc-left-padding;
	box-sizing: border-box;
	overflow-y: auto;
	overflow-x: hidden;
	background-color: @background-color-page-container;

	.sidebar-toc-header {
		padding-bottom: 12px;
	}

	.sidebar-toc-title {
		color: @color-base--subtle;
		font-size: @font-size-base;
		margin: 0;
		padding: 0;
		border: 0;
	}

	.sidebar-toc-numb {
		display: none;
	}

	.sidebar-toc-toggle {
		// For no-js users, toggling is disabled and icon is hidden
		display: none;
		position: absolute;
		top: 1px; // visually center icon
		left: ~'calc( -1 * @{toc-subsection-toggle-icon-size} - 1px )'; // leaves 6px between icon + text
		width: @toc-subsection-toggle-icon-size; // ~22px @ 12
		height: @toc-subsection-toggle-icon-size;
		font-size: 0.75em; // reduces size of toggle icon to 12px @ 16
		transition: @transition-duration-base;
		color: transparent;
		cursor: pointer;
	}

	.sidebar-toc-link {
		word-break: break-word;
		color: @color-link;
		display: block;
	}

	// Highlight and bold active sections, active top sections that are unexpanded
	// and active top sections that are the only active element.
	.sidebar-toc-list-item-active,
	.sidebar-toc-level-1-active:not( .sidebar-toc-list-item-expanded ),
	.sidebar-toc-list-item-active.sidebar-toc-level-1-active {
		> .sidebar-toc-link {
			// Highlight active section
			color: @color-base;
			font-weight: bold;

			.sidebar-toc-text {
				// Increase width to prevent line wrapping due to bold text
				// Avoid applying on link element to avoid focus indicator changing size
				width: ~'calc( 100% + @{sidebar-toc-right-padding} )';
			}
		}
	}

	// Highlight active top sections that contain an active section
	.sidebar-toc-level-1-active:not( .sidebar-toc-list-item-active ) > .sidebar-toc-link {
		color: @color-base;
	}

	.sidebar-toc-text {
		padding: 4px  0;
	}

	.sidebar-toc-contents,
	.sidebar-toc-list {
		margin: 0;
		list-style: none;
		line-height: 18px;
	}

	.sidebar-toc-list-item {
		display: block;
		position: relative;
		list-style-type: none;
		padding-left: 8px;

		&.sidebar-toc-level-1 {
			padding-left: 0;
		}

		a {
			font-size: @font-size-base;
		}
	}
}

// T302076: Add fade scrollable indicator when TOC is in sidebar
// Avoid showing indicator when the TOC is floating, or collapsed in the page title/sticky header
@media ( min-width: @min-width-desktop ) {
	.vector-toc-not-collapsed .sidebar-toc:after {
		content: '';
		display: block;
		position: absolute;
		bottom: 0;
		left: 0;
		right: 0;
		height: @sidebar-toc-fade-height;
		background: linear-gradient( rgba( 255, 255, 255, 0 ), @background-color-page-container );
		background-repeat: no-repeat;
		background-position: -@sidebar-toc-right-padding; // T311436 Hacky way to prevent the fade from covering the scrollbar
		pointer-events: none; // Make the link below the fade clickable
	}
}

// Collapse ToC sections by default, excluding no-js
.client-js .sidebar-toc {
	.sidebar-toc-level-1 .sidebar-toc-list-item {
		display: none;
	}

	.sidebar-toc-level-1.sidebar-toc-list-item-expanded .sidebar-toc-list-item {
		display: block;
	}

	.sidebar-toc-toggle {
		display: block;
	}

	.sidebar-toc-level-1.sidebar-toc-list-item-expanded .sidebar-toc-toggle {
		transform: rotate( 0deg );
	}
}

.client-js body.ltr .sidebar-toc .sidebar-toc-toggle {
	transform: rotate( -90deg );
}

.client-js body.rtl .sidebar-toc .sidebar-toc-toggle {
	transform: rotate( 90deg );
}