/* ── Header Navigation ───────────────────────────────────────── */
.hsk-site-title {
	font-size: var(--text-lg);
	font-weight: 800;
	text-decoration: none;
	color: var(--color-text);
	white-space: nowrap;
	letter-spacing: -0.02em;
	padding-right: var(--space-5);
	margin-right: var(--space-3);
	border-right: 1px solid var(--color-border);
}
.hsk-site-title:hover   { color: var(--color-accent); }
.hsk-site-title:visited { color: var(--color-text); }

.hsk-nav-primary {
	display: flex;
	align-items: center;
	gap: 0;
	flex: 1;
}
.hsk-nav-primary ul {
	display: flex;
	align-items: center;
	gap: 0;
}
.hsk-nav-primary li {
	display: flex;
	align-items: center;
}
/* Separator — visible pipe between items */
.hsk-nav-primary li + li::before {
	content: '';
	display: inline-block;
	width: 1px;
	height: 14px;
	background: #D0D0D0;
	margin: 0 var(--space-2);
	border-radius: 1px;
	flex-shrink: 0;
}
.hsk-nav-primary a {
	display: inline-block;
	padding: var(--space-2) var(--space-2);
	border-radius: var(--radius-md);
	font-size: .8rem;
	font-weight: 500;
	text-decoration: none;
	color: var(--color-text-muted);
	letter-spacing: .01em;
	transition: color var(--trans-fast), background var(--trans-fast);
	white-space: nowrap;
}
.hsk-nav-primary a:hover { color: var(--color-text); background: var(--color-bg-hover); }
.hsk-nav-primary .current-menu-item a {
	color: var(--color-accent);
	font-weight: 700;
}

/* Header search */
.hsk-header-search {
	margin-left: auto;
}
.hsk-header-search form {
	display: flex;
	align-items: stretch;
	gap: 0;
	background: var(--color-bg-soft);
	border: 1.5px solid var(--color-border);
	border-radius: var(--radius-lg);
	overflow: hidden;
	transition: border-color var(--trans-fast), box-shadow var(--trans-fast);
}
.hsk-header-search form:focus-within {
	border-color: var(--color-accent);
	box-shadow: 0 0 0 3px rgba(0,102,204,.12);
}
.hsk-header-search input[type="search"] {
	border: none;
	background: transparent;
	padding: var(--space-2) var(--space-4);
	font-size: var(--text-sm);
	width: 180px;
	color: var(--color-text);
	transition: width var(--trans-base);
	outline: none;
}
.hsk-header-search form:focus-within input[type="search"] { width: 260px; }
.hsk-header-search button[type="submit"] {
	display: flex;
	align-items: center;
	justify-content: center;
	padding: var(--space-3) var(--space-5);
	background: var(--color-accent);
	color: #fff;
	border-radius: 0;
	font-size: var(--text-sm);
	font-weight: 600;
	line-height: 1.2;
	transition: background var(--trans-fast);
	border-left: 1px solid rgba(255,255,255,.2);
}
.hsk-header-search button[type="submit"]:hover { background: var(--color-accent-hover); }

/* Mobile hamburger */
.hsk-menu-toggle {
	display: none;
	padding: var(--space-2) var(--space-3);
	border-radius: var(--radius-md);
	color: var(--color-text);
	font-size: 1.1rem;
	font-weight: 700;
	border: 1px solid var(--color-border);
	transition: background var(--trans-fast);
}
.hsk-menu-toggle:hover { background: var(--color-bg-hover); }

/* ── Sidebar Navigation ──────────────────────────────────────── */
.hsk-sidebar-nav { padding: var(--space-5) 0 var(--space-8); }

/* Section label */
.hsk-sidebar-section-label {
	font-size: .68rem;
	font-weight: 700;
	color: var(--color-text-faint);
	text-transform: uppercase;
	letter-spacing: .1em;
	padding: var(--space-2) var(--space-5) var(--space-3);
}

/* Cluster item */
.hsk-sidebar-cluster { margin-bottom: var(--space-1); }

.hsk-sidebar-cluster-toggle {
	display: flex;
	align-items: center;
	width: 100%;
	padding: var(--space-3) var(--space-5);
	font-size: .82rem;
	font-weight: 600;
	color: var(--color-text);
	text-decoration: none;
	border-radius: 0;
	transition: background var(--trans-fast);
	gap: var(--space-2);
	line-height: 1.4;
}
.hsk-sidebar-cluster-toggle:hover { background: var(--color-bg-hover); color: var(--color-text); }
.hsk-sidebar-cluster-toggle[aria-expanded="true"] { color: var(--color-accent); background: var(--color-bg-soft); }

.hsk-sidebar-cluster-toggle .hsk-chevron {
	font-size: .7rem;
	transition: transform var(--trans-fast);
	flex-shrink: 0;
	margin-left: auto;
	color: var(--color-text-faint);
}
.hsk-sidebar-cluster-toggle[aria-expanded="true"] .hsk-chevron { transform: rotate(180deg); color: var(--color-accent); }

.hsk-sidebar-cluster-count {
	font-size: .72rem;
	color: var(--color-text-faint);
	font-weight: 400;
	background: var(--color-bg-hover);
	border-radius: 999px;
	padding: 1px 6px;
}

/* Article list */
.hsk-sidebar-articles {
	display: none;
	padding-left: var(--space-4);
	padding-bottom: var(--space-2);
	border-left: 2px solid var(--color-border);
	margin-left: var(--space-5);
	margin-right: var(--space-3);
	margin-bottom: var(--space-2);
}
.hsk-sidebar-articles.is-open { display: block; }

.hsk-sidebar-article {
	display: block;
	padding: var(--space-2) var(--space-3);
	font-size: .8rem;
	color: var(--color-text-muted);
	text-decoration: none;
	border-radius: var(--radius-md);
	line-height: 1.45;
	transition: color var(--trans-fast), background var(--trans-fast);
}
.hsk-sidebar-article:hover {
	color: var(--color-text);
	background: var(--color-bg-hover);
}
.hsk-sidebar-article.is-current {
	color: var(--color-accent);
	background: rgba(0,102,204,.06);
	font-weight: 600;
}
.hsk-sidebar-article.is-pillar {
	font-weight: 700;
	color: var(--color-text);
}
.hsk-sidebar-article.is-pillar::before {
	content: '★ ';
	color: var(--color-accent);
	font-size: .8em;
}

/* ── Context (TOC) sidebar ───────────────────────────────────── */
.hsk-toc-title {
	font-size: var(--text-sm);
	font-weight: 700;
	text-transform: uppercase;
	letter-spacing: .07em;
	color: var(--color-text-faint);
	margin-bottom: var(--space-3);
}
.hsk-toc-list { padding: 0; }
.hsk-toc-list li { margin-bottom: var(--space-1); }
.hsk-toc-list a {
	display: block;
	font-size: var(--text-sm);
	color: var(--color-text-muted);
	text-decoration: none;
	padding: var(--space-1) var(--space-2);
	border-left: 2px solid transparent;
	border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
	transition: color var(--trans-fast), border-color var(--trans-fast);
}
.hsk-toc-list a:hover { color: var(--color-text); }
.hsk-toc-list a.is-active { color: var(--color-accent); border-left-color: var(--color-accent); }
.hsk-toc-list .toc-h3 { padding-left: var(--space-5); font-size: .8rem; }

/* Read progress bar */
.hsk-progress-bar {
	position: fixed;
	top: 0;
	left: 0;
	width: 0%;
	height: 3px;
	background: var(--color-accent);
	z-index: 9999;
	transition: width 100ms linear;
}