/* SynthesizedHuman Foundations — long-form reading (tokens aligned with BRANDING.md) */

:root {
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-full: 999px;
  --font-sans: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "Cascadia Code", "SF Mono", Consolas, monospace;
  --leading-tight: 1.15;
  --leading-normal: 1.65;
  --tracking-tight: -0.03em;
  --tracking-widest: 0.22em;
  --ease-ui: cubic-bezier(0.16, 1, 0.3, 1);
  --duration-base: 160ms;
  --read-width: 42rem;
  --layout-max: 72rem;
}

[data-theme="dark"],
:root {
  color-scheme: dark;
  --color-canvas: #03060e;
  --color-surface-1: #061226;
  --color-surface-2: #0a1d3a;
  --color-elevated: #142845;
  --color-text-primary: #dcecff;
  --color-text-secondary: #aebfd6;
  --color-text-muted: #7f93b0;
  --color-text-faint: #4a6080;
  --color-accent: #4fd6ff;
  --color-accent-hover: #82e4ff;
  --color-accent-subtle: rgba(79, 214, 255, 0.1);
  --color-accent-border: rgba(79, 214, 255, 0.22);
  --color-border: #142845;
  --color-border-strong: #1e3a5f;
}

[data-theme="light"] {
  color-scheme: light;
  --color-canvas: #f8fafc;
  --color-surface-1: #ffffff;
  --color-surface-2: #f0f4f8;
  --color-elevated: #ffffff;
  --color-text-primary: #0d1b2e;
  --color-text-secondary: #2e4a6a;
  --color-text-muted: #5a7898;
  --color-text-faint: #9ab0c8;
  --color-accent: #0a7ec2;
  --color-accent-hover: #0660a0;
  --color-accent-subtle: rgba(10, 126, 194, 0.08);
  --color-accent-border: rgba(10, 126, 194, 0.2);
  --color-border: #d0dce8;
  --color-border-strong: #a8bcd0;
}

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

html {
  scroll-behavior: smooth;
}

body.foundations-page {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: var(--leading-normal);
  color: var(--color-text-primary);
  background: radial-gradient(ellipse 120% 80% at 50% -20%, var(--color-surface-2), var(--color-canvas));
  background-attachment: fixed;
}

.read-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  width: 0%;
  background: var(--color-accent);
  z-index: 400;
  transition: width 80ms linear;
}

#site-nav {
  position: sticky;
  top: 0;
  z-index: 300;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) var(--space-6);
  border-bottom: 1px solid var(--color-border);
  background: color-mix(in srgb, var(--color-canvas) 88%, transparent);
  backdrop-filter: blur(12px);
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  color: var(--color-text-primary);
}

.nav-mark svg {
  width: 36px;
  height: 36px;
  display: block;
}

.nav-wordmark {
  font-weight: 600;
  letter-spacing: var(--tracking-tight);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.nav-actions a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--duration-base) var(--ease-ui);
}

.nav-actions a:hover,
.nav-actions a.is-active {
  color: var(--color-accent);
}

.btn-theme {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  background: var(--color-surface-1);
  color: var(--color-text-secondary);
  cursor: pointer;
}

.btn-theme:hover {
  border-color: var(--color-accent-border);
  color: var(--color-text-primary);
}

/* Hub */
.hub-main {
  max-width: var(--layout-max);
  margin: 0 auto;
  padding: var(--space-12) var(--space-6) var(--space-16);
}

.hub-hero {
  max-width: 40rem;
  margin-bottom: var(--space-12);
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
  color: var(--color-text-faint);
  margin: 0 0 var(--space-4);
}

.hub-hero h1 {
  font-size: clamp(2.25rem, 5vw, 3.5rem);
  font-weight: 800;
  letter-spacing: var(--tracking-tight);
  line-height: var(--leading-tight);
  margin: 0 0 var(--space-4);
}

.hub-tagline {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  margin: 0;
}

.hub-section-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
  color: var(--color-text-faint);
  margin: 0 0 var(--space-4);
}

.featured-card {
  padding: var(--space-8);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-accent-border);
  background: var(--color-accent-subtle);
  margin-bottom: var(--space-12);
}

.featured-card h2 {
  font-size: clamp(1.5rem, 3vw, 2rem);
  margin: var(--space-2) 0 var(--space-4);
  letter-spacing: var(--tracking-tight);
}

.featured-card h2 a {
  color: inherit;
  text-decoration: none;
}

.featured-card h2 a:hover {
  color: var(--color-accent);
}

.featured-abstract {
  color: var(--color-text-secondary);
  max-width: 50ch;
  margin: 0 0 var(--space-6);
}

.pub-type {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-faint);
  margin: 0;
}

.pub-meta {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

.pub-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--color-border);
}

.pub-list li {
  border-bottom: 1px solid var(--color-border);
}

.pub-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding: var(--space-5) 0;
  text-decoration: none;
  color: inherit;
  transition: color var(--duration-base) var(--ease-ui);
}

.pub-row:hover {
  color: var(--color-accent);
}

.pub-row-main {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.pub-row-title {
  font-weight: 600;
  font-size: 1.05rem;
}

.hub-footer {
  margin-top: var(--space-16);
  padding-top: var(--space-8);
  border-top: 1px solid var(--color-border);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-4);
}

.hub-footer p {
  margin: 0;
  color: var(--color-text-muted);
}

.btn-primary,
.btn-secondary,
.btn-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 0.875rem;
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-md);
  text-decoration: none;
  cursor: pointer;
  border: none;
  font-family: inherit;
  transition:
    background var(--duration-base) var(--ease-ui),
    border-color var(--duration-base) var(--ease-ui),
    color var(--duration-base) var(--ease-ui);
}

.btn-primary {
  background: var(--color-accent);
  color: var(--color-canvas);
}

.btn-primary:hover {
  background: var(--color-accent-hover);
}

.btn-secondary {
  background: transparent;
  border: 1px solid var(--color-border-strong);
  color: var(--color-text-primary);
}

.btn-secondary:hover {
  border-color: var(--color-accent-border);
}

.btn-ghost {
  background: transparent;
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
}

.btn-ghost:hover {
  color: var(--color-accent);
  border-color: var(--color-accent-border);
}

/* Article layout */
.article-layout {
  max-width: var(--layout-max);
  margin: 0 auto;
  padding: var(--space-8) var(--space-6) var(--space-16);
  display: grid;
  grid-template-columns: 14rem minmax(0, 1fr);
  gap: var(--space-10);
  align-items: start;
}

.article-toc {
  position: sticky;
  top: 5rem;
  max-height: calc(100vh - 6rem);
  overflow-y: auto;
  padding-right: var(--space-4);
}

.toc-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
  color: var(--color-text-faint);
  margin: 0 0 var(--space-3);
}

.article-toc nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.article-toc a {
  display: block;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  text-decoration: none;
  padding: var(--space-2) 0;
  border-left: 2px solid transparent;
  padding-left: var(--space-3);
  line-height: 1.4;
}

.article-toc a:hover,
.article-toc a.is-active {
  color: var(--color-accent);
  border-left-color: var(--color-accent);
}

.article-main {
  max-width: calc(var(--read-width) + 2rem);
}

.article-header {
  margin-bottom: var(--space-10);
  padding-bottom: var(--space-8);
  border-bottom: 1px solid var(--color-border);
}

.article-header h1 {
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 800;
  letter-spacing: var(--tracking-tight);
  line-height: var(--leading-tight);
  margin: var(--space-3) 0;
}

.article-subtitle {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  margin: 0 0 var(--space-4);
}

.article-byline {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-text-muted);
  margin: 0 0 var(--space-5);
}

.article-byline .sep {
  margin: 0 var(--space-2);
  opacity: 0.5;
}

.article-abstract {
  font-size: 1.05rem;
  color: var(--color-text-secondary);
  margin: 0;
  max-width: 55ch;
}

/* Prose */
.prose {
  color: var(--color-text-primary);
}

.prose h2 {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: var(--tracking-tight);
  margin: var(--space-12) 0 var(--space-4);
  scroll-margin-top: 5rem;
}

.prose h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin: var(--space-8) 0 var(--space-3);
  scroll-margin-top: 5rem;
}

.prose p {
  margin: 0 0 var(--space-5);
}

.prose ul,
.prose ol {
  margin: 0 0 var(--space-5);
  padding-left: var(--space-6);
}

.prose li {
  margin-bottom: var(--space-2);
}

.prose strong {
  font-weight: 600;
  color: var(--color-text-primary);
}

.prose em {
  color: var(--color-text-secondary);
}

.prose hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: var(--space-10) 0;
}

.prose a {
  color: var(--color-accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
}

.prose blockquote {
  margin: var(--space-6) 0;
  padding: var(--space-4) var(--space-5);
  border-left: 3px solid var(--color-accent-border);
  background: var(--color-accent-subtle);
  color: var(--color-text-secondary);
}

.continue-exploring {
  margin-top: var(--space-16);
  padding-top: var(--space-10);
  border-top: 1px solid var(--color-border);
}

.continue-exploring h2 {
  font-size: 1.25rem;
  margin: 0 0 var(--space-6);
}

.continue-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(12rem, 1fr));
  gap: var(--space-4);
  margin-bottom: var(--space-6);
}

.continue-card {
  display: block;
  padding: var(--space-5);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  background: var(--color-surface-1);
  text-decoration: none;
  color: inherit;
  transition: border-color var(--duration-base) var(--ease-ui);
}

.continue-card:hover {
  border-color: var(--color-accent-border);
}

.continue-label {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
  color: var(--color-text-faint);
  margin-bottom: var(--space-2);
}

.continue-title {
  font-weight: 600;
  font-size: 0.95rem;
}

.product-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-bottom: var(--space-6);
}

.product-link {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-accent);
}

.share-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

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

  .article-toc {
    position: relative;
    top: 0;
    max-height: none;
    border-bottom: 1px solid var(--color-border);
    padding-bottom: var(--space-6);
    margin-bottom: var(--space-4);
  }
}

@media (max-width: 600px) {
  #site-nav {
    padding: var(--space-3) var(--space-4);
  }

  .nav-wordmark {
    display: none;
  }

  .hub-main,
  .article-layout {
    padding-left: var(--space-4);
    padding-right: var(--space-4);
  }
}