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

@subcategory-padding: 8px;
@fade-height: 40px;
@vertical-padding: 20px;
@toggle-icon-size: 1.834em;

.sidebar-toc {
	display: none;
	width: @width-sidebar;
	max-height: 75vh;
	padding: @vertical-padding @subcategory-padding @vertical-padding ~'calc( @{subcategory-padding} * 4 )';
	.box-sizing( border-box );
	overflow: auto;
	background-color: @border-color-sidebar;

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

	.sidebar-toc-title {
		font-weight: bold;
		font-size: @font-size-reset;
		margin: 0;
		padding: 0;
		border: 0;
	}

	.sidebar-toc-link > * {
		// Prevent click events on the link's contents so that we can use event
		// delegation and have the target be the anchor element instead.
		pointer-events: none;
	}

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

	.sidebar-toc-text {
		padding: ~'calc( @{subcategory-padding} / 2 )'  0;
	}

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

	.sidebar-toc-contents {
		padding-bottom: ~'calc( @{vertical-padding} / 2 )';
	}

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

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

	.sidebar-toc-list-item.sidebar-toc-level-1 {
		padding-left: 0;

		& > a {
			color: @color-link;
		}
	}
}

// Hide scrollbar but allow scrolling for Chrome, Safari, and Opera
.sidebar-toc::-webkit-scrollbar {
	display: none;
}

// T302076 Add scrollable indicator as fade
.sidebar-toc:after {
	content: '';
	display: block;
	position: absolute;
	bottom: 0;
	left: 0;
	right: 0;
	height: @fade-height;
	background: linear-gradient( rgba( 255, 255, 255, 0 ), @border-color-sidebar );
	pointer-events: none; // Make the link below the fade clickable
	margin: 0 @border-width-base;
}

// Highlight active section
.sidebar-toc .sidebar-toc-list-item-active > .sidebar-toc-link {
	font-weight: bold;
}

.sidebar-toc .sidebar-toc-toggle {
	// For no-js users, toggling is disabled and icon is hidden
	display: none;
	cursor: pointer;
}

// Collapse ToC sections by default, excluding no-js or prefers-reduced-motion
@media ( prefers-reduced-motion: no-preference ) {
	.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 {
			position: absolute;
			top: 1px; // visually center icon
			left: ~'calc( -1 * @{toggle-icon-size} - 1px )'; // leaves 6px between icon + text
			display: block;
			width: @toggle-icon-size; // ~22px @ 12
			height: @toggle-icon-size;
			font-size: 0.75em; // reduces size of toggle icon to 12px @ 16
			transform: rotate( -90deg );
			transition: 100ms;
		}

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

@media ( min-width: @width-breakpoint-tablet ) {
	.sidebar-toc {
		display: block;
	}
}

// T300975 following media query for TOC experiment treatment
// class can be removed once associated A/B test is over.
@media ( max-width: @width-breakpoint-tablet ) {
	.skin-vector-toc-experiment-treatment #toc {
		display: table;
	}
}