:root {
	--color-bg: #fafbfc;
	--color-surface: #ffffff;
	--color-text: #1a1d21;
	--color-muted: #5c6570;
	--color-border: #e2e6eb;
	--color-accent: #0b5fff;
	--color-accent-hover: #0847c4;
	--radius: 10px;
	--shadow: 0 1px 2px rgba(16, 24, 40, 0.06), 0 4px 12px rgba(16, 24, 40, 0.04);
	--space-xs: 0.35rem;
	--space-sm: 0.75rem;
	--space-md: 1.25rem;
	--space-lg: 2rem;
	--space-xl: 3rem;
	--maxw: 72rem;
	--font: system-ui, -apple-system, "Segoe UI", Roboto, Ubuntu, Cantarell, "Noto Sans", sans-serif;
}

*,
*::before,
*::after {
	box-sizing: border-box;
}

html {
	scroll-behavior: smooth;
}

body {
	margin: 0;
	font-family: var(--font);
	font-size: 1.05rem;
	line-height: 1.65;
	color: var(--color-text);
	background: var(--color-bg);
}

a {
	color: var(--color-accent);
	text-decoration-thickness: 1px;
	text-underline-offset: 0.15em;
}

a:hover {
	color: var(--color-accent-hover);
}

.isoc-wrap {
	width: min(100% - 2rem, var(--maxw));
	margin-inline: auto;
}

.isoc-skip-link {
	position: absolute;
	left: -9999px;
	z-index: 1000;
	padding: 0.5rem 1rem;
	background: var(--color-accent);
	color: #fff;
}

.isoc-skip-link:focus {
	left: 0.5rem;
	top: 0.5rem;
}

/* Header */
.isoc-site-header {
	background: var(--color-surface);
	border-bottom: 1px solid var(--color-border);
	position: sticky;
	top: 0;
	z-index: 50;
}

.isoc-header-inner {
	display: flex;
	align-items: center;
	gap: var(--space-md);
	padding-block: var(--space-sm);
	flex-wrap: wrap;
}

.isoc-primary-nav-wrap {
	flex: 1 1 auto;
	min-width: 0;
}

.isoc-header-tools {
	margin-left: auto;
	display: flex;
	align-items: center;
	gap: var(--space-sm);
}

.isoc-brand {
	font-weight: 700;
	font-size: 1.1rem;
	color: var(--color-text);
	text-decoration: none;
}

.isoc-brand:hover {
	color: var(--color-text);
}

.isoc-nav-toggle {
	display: none;
	border: 1px solid var(--color-border);
	background: var(--color-surface);
	border-radius: var(--radius);
	padding: 0.45rem 0.65rem;
	font: inherit;
	cursor: pointer;
}

.isoc-primary-nav ul {
	list-style: none;
	margin: 0;
	padding: 0;
	display: flex;
	flex-wrap: wrap;
	gap: 0.25rem 1rem;
	align-items: center;
}

.isoc-primary-nav a {
	color: var(--color-text);
	font-weight: 500;
	text-decoration: none;
}

.isoc-primary-nav a:hover {
	color: var(--color-accent);
}

.isoc-lang-switcher {
	font-size: 0.9rem;
	color: var(--color-muted);
}

.isoc-lang-switcher ul {
	list-style: none;
	margin: 0;
	padding: 0;
	display: flex;
	gap: 0.5rem;
	flex-wrap: wrap;
}

.isoc-lang-switcher a {
	font-weight: 600;
}

/* Hero & sections */
.isoc-hero {
	padding: var(--space-xl) 0 var(--space-lg);
	background: linear-gradient(180deg, #eef3ff 0%, var(--color-bg) 100%);
}

.isoc-hero h1 {
	font-size: clamp(1.75rem, 4vw, 2.5rem);
	line-height: 1.2;
	margin: 0 0 var(--space-sm);
}

.isoc-hero p {
	max-width: 42rem;
	color: var(--color-muted);
	margin: 0;
}

.isoc-section {
	padding: var(--space-lg) 0;
}

.isoc-section h2 {
	font-size: 1.35rem;
	margin: 0 0 var(--space-md);
}

.isoc-card-grid {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr));
	gap: var(--space-md);
}

.isoc-card {
	background: var(--color-surface);
	border: 1px solid var(--color-border);
	border-radius: var(--radius);
	padding: var(--space-md);
	box-shadow: var(--shadow);
}

.isoc-card h3 {
	margin-top: 0;
	font-size: 1.1rem;
}

.isoc-card p {
	color: var(--color-muted);
	margin-bottom: 0;
	font-size: 0.95rem;
}

/* Landing layout */
.isoc-landing {
	padding-bottom: var(--space-xl);
}

.isoc-landing-intro {
	color: var(--color-muted);
	font-size: 1.1rem;
	max-width: 48rem;
}

.isoc-landing-layout {
	display: grid;
	grid-template-columns: minmax(0, 1fr) 16rem;
	gap: var(--space-lg);
	align-items: start;
	margin-top: var(--space-lg);
}

.isoc-landing-layout--single {
	grid-template-columns: minmax(0, 1fr);
}

@media (max-width: 900px) {
	.isoc-landing-layout {
		grid-template-columns: 1fr;
	}
}

.isoc-toc {
	position: sticky;
	top: 5.5rem;
	background: var(--color-surface);
	border: 1px solid var(--color-border);
	border-radius: var(--radius);
	padding: var(--space-md);
	font-size: 0.95rem;
}

.isoc-toc h2 {
	font-size: 0.85rem;
	text-transform: uppercase;
	letter-spacing: 0.04em;
	color: var(--color-muted);
	margin: 0 0 var(--space-sm);
}

.isoc-toc ol {
	margin: 0;
	padding-left: 1.1rem;
}

.isoc-toc a {
	color: var(--color-text);
	text-decoration: none;
}

.isoc-toc a:hover {
	color: var(--color-accent);
}

.isoc-prose {
	max-width: 48rem;
}

.isoc-prose > *:first-child {
	margin-top: 0;
}

.isoc-prose h2,
.isoc-prose h3 {
	scroll-margin-top: 5rem;
}

.isoc-takeaways,
.isoc-faq,
.isoc-related {
	margin-top: var(--space-lg);
	padding: var(--space-md);
	background: var(--color-surface);
	border: 1px solid var(--color-border);
	border-radius: var(--radius);
}

.isoc-takeaways ul,
.isoc-faq dl {
	margin: 0;
}

.isoc-faq dt {
	font-weight: 700;
	margin-top: var(--space-sm);
}

.isoc-faq dt:first-child {
	margin-top: 0;
}

.isoc-faq dd {
	margin: var(--space-xs) 0 0;
	color: var(--color-muted);
}

/* Breadcrumb */
.isoc-breadcrumb {
	font-size: 0.9rem;
	color: var(--color-muted);
	margin-bottom: var(--space-md);
}

.isoc-breadcrumb ol {
	list-style: none;
	margin: 0;
	padding: 0;
	display: flex;
	flex-wrap: wrap;
	gap: 0.35rem;
}

.isoc-breadcrumb li:not(:last-child)::after {
	content: "/";
	margin-left: 0.35rem;
	color: var(--color-border);
}

.isoc-breadcrumb a {
	color: var(--color-muted);
}

/* CTA */
.isoc-cta {
	border-radius: var(--radius);
	padding: var(--space-md);
	background: #0f172a;
	color: #e8eefc;
	margin: var(--space-lg) 0;
}

.isoc-cta--inline {
	background: #f0f4ff;
	color: var(--color-text);
	border: 1px solid #c7d7ff;
}

.isoc-cta--bottom {
	background: linear-gradient(135deg, #0b5fff 0%, #3730a3 100%);
}

.isoc-cta--checklist {
	border-left: 4px solid var(--color-accent);
	background: var(--color-surface);
	color: var(--color-text);
	border: 1px solid var(--color-border);
	border-left-width: 4px;
}

.isoc-cta--scan {
	background: #102a43;
}

.isoc-cta--compare {
	background: #1b4332;
}

.isoc-cta h3,
.isoc-cta .isoc-cta__title {
	margin: 0 0 var(--space-xs);
	font-size: 1.15rem;
}

.isoc-cta p {
	margin: 0 0 var(--space-sm);
	color: inherit;
	opacity: 0.92;
}

.isoc-cta .button,
.isoc-cta a.isoc-button {
	display: inline-block;
	background: #fff;
	color: #0b5fff;
	font-weight: 600;
	padding: 0.55rem 1rem;
	border-radius: 999px;
	text-decoration: none;
}

.isoc-cta--inline a.isoc-button {
	background: var(--color-accent);
	color: #fff;
}

.isoc-cta--bottom a.isoc-button {
	background: #fff;
	color: #3730a3;
}

/* Footer */
.isoc-site-footer {
	background: #0f172a;
	color: #cbd5e1;
	padding: var(--space-lg) 0;
	margin-top: var(--space-xl);
	font-size: 0.95rem;
}

.isoc-site-footer a {
	color: #e2e8f0;
}

.isoc-footer-grid {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(12rem, 1fr));
	gap: var(--space-md);
}

.isoc-footer-bottom {
	margin-top: var(--space-md);
	padding-top: var(--space-md);
	border-top: 1px solid rgba(255, 255, 255, 0.12);
	font-size: 0.85rem;
	color: #94a3b8;
}

.isoc-footer-menu {
	list-style: none;
	margin: 0.5rem 0 0;
	padding: 0;
}

.isoc-footer-menu li {
	margin: 0.25rem 0;
}

/* Mobile nav */
@media (max-width: 768px) {
	.isoc-brand {
		order: 1;
	}

	.isoc-nav-toggle {
		display: inline-flex;
		order: 2;
		margin-left: auto;
	}

	.isoc-header-tools {
		order: 3;
		margin-left: 0;
	}

	.isoc-primary-nav-wrap {
		order: 4;
		width: 100%;
		flex-basis: 100%;
		max-height: 0;
		overflow: hidden;
		transition: max-height 0.25s ease;
	}

	.isoc-site-header.isoc-nav-open .isoc-primary-nav-wrap {
		max-height: 24rem;
	}

	.isoc-primary-nav ul {
		flex-direction: column;
		align-items: flex-start;
		padding: var(--space-sm) 0;
	}

	.isoc-toc {
		position: static;
	}
}