/* Base typography, page structure, header, footer and layout primitives (mobile-first). */

/* ---------- Base ---------- */

html {
  color-scheme: light;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + var(--space-4));
}

body {
  font-family: var(--font-sans);
  font-size: var(--fs-base);
  line-height: var(--lh-body);
  color: var(--color-text);
  background: var(--color-bg);
}

html.nav-open {
  overflow: hidden;
}

h1,
h2,
h3,
h4 {
  color: var(--color-heading);
  line-height: var(--lh-tight);
  font-weight: var(--fw-bold);
  letter-spacing: -0.02em;
}

h1 {
  font-size: var(--fs-3xl);
}

h2 {
  font-size: var(--fs-2xl);
}

h3 {
  font-size: var(--fs-lg);
  line-height: var(--lh-snug);
  letter-spacing: -0.01em;
}

h4 {
  font-size: var(--fs-base);
  line-height: var(--lh-snug);
  letter-spacing: 0;
}

a {
  color: var(--color-primary);
  text-underline-offset: 0.18em;
  text-decoration-thickness: 1px;
}

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

strong {
  font-weight: var(--fw-semibold);
  color: var(--color-heading);
}

:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
  border-radius: 4px;
}

::selection {
  background: var(--color-primary-soft);
  color: var(--color-ink-900);
}

.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  left: var(--space-4);
  top: -100px;
  z-index: 100;
  padding: var(--space-3) var(--space-4);
  background: var(--color-ink-900);
  color: #fff;
  border-radius: var(--radius-sm);
  font-weight: var(--fw-semibold);
  text-decoration: none;
}

.skip-link:focus {
  top: var(--space-3);
  color: #fff;
}

/* ---------- Text helpers ---------- */

.eyebrow {
  display: inline-block;
  margin-bottom: var(--space-3);
  font-size: var(--fs-sm);
  font-weight: var(--fw-semibold);
  letter-spacing: 0.02em;
  color: var(--color-primary);
}

.lead {
  font-size: var(--fs-md);
  color: var(--color-muted);
  line-height: 1.65;
}

.text-muted {
  color: var(--color-muted);
}

.text-small {
  font-size: var(--fs-sm);
}

.text-center {
  text-align: center;
}

.num {
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

/* ---------- Containers & sections ---------- */

.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--container-gutter);
}

.container--narrow {
  max-width: calc(var(--container-narrow) + 2 * var(--container-gutter));
}

.section {
  padding-block: var(--section-space);
}

.section--tight {
  padding-block: calc(var(--section-space) * 0.6);
}

.section--alt {
  background: var(--color-bg-alt);
}

.section--surface {
  background: var(--color-surface);
  border-block: 1px solid var(--color-border);
}

.section--dark {
  background: var(--color-dark);
  color: var(--color-on-dark);
}

.section--dark h2,
.section--dark h3,
.section--dark strong {
  color: #fff;
}

.section--dark .eyebrow {
  color: #8fd1bf;
}

.section--dark .lead,
.section--dark .text-muted {
  color: var(--color-on-dark-muted);
}

.section-header {
  max-width: 46rem;
  margin-bottom: var(--space-12);
}

.section-header > * + * {
  margin-top: var(--space-4);
}

.section-header--center {
  margin-inline: auto;
  text-align: center;
}

.section-footer {
  margin-top: var(--space-10);
}

/* ---------- Layout primitives ---------- */

.stack > * + * {
  margin-top: var(--stack-space, var(--space-4));
}

.stack--lg {
  --stack-space: var(--space-6);
}

.cluster {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-3);
}

.cluster--center {
  justify-content: center;
}

.heading-sm {
  font-size: var(--fs-xl);
}

.grid {
  display: grid;
  gap: var(--space-5);
  grid-template-columns: minmax(0, 1fr);
}

.split {
  display: grid;
  gap: var(--space-12);
  align-items: center;
  grid-template-columns: minmax(0, 1fr);
}

.split--top {
  align-items: start;
}

/* ---------- Header ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--color-bg);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition-base), box-shadow var(--transition-base);
}

.site-header.is-scrolled,
.site-header.is-open {
  border-bottom-color: var(--color-border);
  box-shadow: var(--shadow-xs);
}

.site-header__inner {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  height: var(--header-height);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
  color: var(--color-ink-900);
  font-size: 1.25rem;
  font-weight: var(--fw-bold);
  letter-spacing: -0.03em;
  text-decoration: none;
}

.brand:hover {
  color: var(--color-ink-900);
}

.brand__mark {
  width: 30px;
  height: 30px;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-left: auto;
}

.header-actions .header-actions__login {
  display: none;
}

/* ---------- Main ---------- */

main {
  display: block;
}

main:focus {
  outline: none;
}

/* ---------- Inner page hero ---------- */

.page-hero {
  padding-block: var(--space-10) var(--space-16);
}

.page-hero__content {
  max-width: 48rem;
}

.page-hero__content > * + * {
  margin-top: var(--space-5);
}

.page-hero h1 {
  font-size: var(--fs-3xl);
}

.breadcrumbs {
  margin-bottom: var(--space-8);
  font-size: var(--fs-sm);
}

.breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  padding: 0;
  list-style: none;
  color: var(--color-muted);
}

.breadcrumbs li + li::before {
  content: "/";
  margin-right: var(--space-2);
  color: var(--color-ink-300);
}

.breadcrumbs a {
  color: var(--color-muted);
  text-decoration: none;
}

.breadcrumbs a:hover {
  color: var(--color-primary);
  text-decoration: underline;
}

/* ---------- Footer ---------- */

.site-footer {
  padding-block: var(--space-16) var(--space-8);
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  font-size: var(--fs-sm);
}

.footer-grid {
  display: grid;
  gap: var(--space-10);
  grid-template-columns: minmax(0, 1fr);
}

.footer-brand > * + * {
  margin-top: var(--space-3);
}

.footer-brand__tagline {
  font-size: var(--fs-base);
  font-weight: var(--fw-semibold);
  color: var(--color-heading);
}

.footer-brand__desc {
  max-width: 22rem;
  color: var(--color-muted);
}

.footer-nav {
  display: grid;
  gap: var(--space-8);
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.footer-heading {
  margin-bottom: var(--space-3);
  font-size: var(--fs-sm);
  font-weight: var(--fw-semibold);
  letter-spacing: 0;
  color: var(--color-heading);
}

.footer-links {
  padding: 0;
  list-style: none;
}

.footer-links li + li {
  margin-top: var(--space-2);
}

.footer-links a {
  display: inline-block;
  padding-block: 2px;
  color: var(--color-muted);
  text-decoration: none;
}

.footer-links a:hover {
  color: var(--color-primary);
  text-decoration: underline;
}

.footer-bottom {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  margin-top: var(--space-12);
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-border);
  color: var(--color-muted);
}

.footer-bottom a {
  color: var(--color-muted);
}

.footer-disclaimer {
  max-width: 48rem;
  font-size: var(--fs-xs);
  line-height: 1.6;
}