/* /learn/ — mirrors ChooseOut tokens, self-contained, no Tailwind. */
:root {
  --bg: #F9F9F8;
  --fg: #1A1A1A;
  --muted: #6F6F6C;
  --card: #FFFFFF;
  --border: #E7E7E5;
  --warm: #E56B3A;
  --warm-soft: #FFF5EE;
  --shadow-subtle: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-default: 0 2px 8px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.04);
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
}
.dark {
  --bg: #141418;
  --fg: #E8E8E8;
  --muted: #A6A6AD;
  --card: #2E2E35;
  --border: #454551;
  --warm: #D4734E;
  --warm-soft: #3A2A22;
  --shadow-subtle: 0 1px 2px rgba(0,0,0,0.2);
  --shadow-default: 0 2px 8px rgba(0,0,0,0.3), 0 1px 2px rgba(0,0,0,0.15);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--fg);
  background: var(--bg);
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)' opacity='0.03'/%3E%3C/svg%3E");
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  letter-spacing: 0.005em;
}
a { color: var(--warm); text-decoration: none; }
a:hover { text-decoration: underline; }

/* nav */
.site-nav { position: sticky; top: 0; z-index: 30; background: rgba(249,249,248,0.85); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); border-bottom: 1px solid var(--border); }
.dark .site-nav { background: rgba(20,20,24,0.85); }
.nav-inner { max-width: 64rem; margin: 0 auto; padding: 0.75rem 1.25rem; display: flex; align-items: center; justify-content: space-between; }
.nav-brand { display: inline-flex; align-items: center; gap: 0.5rem; font-weight: 700; letter-spacing: -0.025em; color: var(--fg); font-size: 1.05rem; }
.nav-brand img { display: block; }
.nav-links { display: flex; align-items: center; gap: 0.75rem; }
.nav-link { color: var(--muted); font-size: 0.875rem; font-weight: 500; }
.nav-link:hover { color: var(--fg); text-decoration: none; }

/* buttons */
.btn { display: inline-flex; align-items: center; justify-content: center; padding: 0 1rem; height: 2.25rem; border-radius: var(--radius-md); font-weight: 500; font-size: 0.875rem; transition: opacity .15s, background .15s; cursor: pointer; }
.btn-primary { background: var(--fg); color: var(--bg); }
.btn-primary:hover { opacity: 0.9; text-decoration: none; }
.btn-ghost { background: transparent; color: var(--fg); border: 1px solid var(--border); }
.btn-ghost:hover { background: var(--warm-soft); text-decoration: none; }

/* hub */
.hub-shell { max-width: 64rem; margin: 0 auto; padding: 3rem 1.25rem 5rem; }
.hub-hero { max-width: 38rem; margin-bottom: 4rem; }
.hub-eyebrow { font-size: 0.75rem; font-weight: 600; letter-spacing: 0.15em; text-transform: uppercase; color: var(--warm); margin: 0 0 0.75rem; }
.hub-title { font-size: clamp(2rem, 4.5vw, 3.25rem); font-weight: 700; letter-spacing: -0.035em; line-height: 1.1; margin: 0 0 1.25rem; }
.hub-title .accent { font-weight: 400; color: var(--warm); }
.hub-lede { font-size: 1.0625rem; line-height: 1.55; color: var(--muted); margin: 0 0 1.75rem; }
.hub-cta-row { display: flex; gap: 0.75rem; flex-wrap: wrap; }
.hub-cat { margin-bottom: 3rem; }
.hub-cat-title { font-size: 1.25rem; font-weight: 700; letter-spacing: -0.025em; margin: 0 0 1rem; padding-bottom: 0.5rem; border-bottom: 1px solid var(--border); }
.hub-grid { display: grid; grid-template-columns: 1fr; gap: 0.875rem; }
@media (min-width: 640px) { .hub-grid { grid-template-columns: 1fr 1fr; } }
@media (min-width: 960px) { .hub-grid { grid-template-columns: 1fr 1fr 1fr; } }
.hub-card { display: flex; flex-direction: column; padding: 1.25rem; background: var(--card); border: 1px solid var(--border); border-radius: var(--radius-md); box-shadow: var(--shadow-subtle); transition: box-shadow .2s, border-color .2s, transform .2s; color: var(--fg); }
.hub-card:hover { box-shadow: var(--shadow-default); border-color: var(--warm); transform: translateY(-1px); text-decoration: none; }
.hub-card-title { font-size: 1rem; font-weight: 600; letter-spacing: -0.015em; margin: 0 0 0.5rem; line-height: 1.3; }
.hub-card-desc { font-size: 0.875rem; color: var(--muted); margin: 0 0 0.75rem; line-height: 1.5; flex: 1; }
.hub-card-arrow { font-size: 0.8125rem; color: var(--warm); font-weight: 500; }

/* article */
.article-shell { max-width: 44rem; margin: 0 auto; padding: 2rem 1.25rem 5rem; }
.breadcrumb { font-size: 0.8125rem; color: var(--muted); margin-bottom: 1.5rem; display: flex; flex-wrap: wrap; gap: 0.4rem; align-items: center; }
.breadcrumb a { color: var(--muted); }
.breadcrumb a:hover { color: var(--fg); text-decoration: none; }
.article-eyebrow { font-size: 0.75rem; font-weight: 600; letter-spacing: 0.15em; text-transform: uppercase; color: var(--warm); margin: 0 0 0.75rem; }
.article-title { font-size: clamp(1.875rem, 4vw, 2.75rem); font-weight: 700; letter-spacing: -0.035em; line-height: 1.15; margin: 0 0 1rem; }
.article-lede { font-size: 1.125rem; line-height: 1.55; color: var(--muted); margin: 0 0 1rem; }
.article-meta { font-size: 0.8125rem; color: var(--muted); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); padding: 0.625rem 0; margin: 1.5rem 0 2rem; }

.article-body h2 { font-size: 1.5rem; font-weight: 700; letter-spacing: -0.025em; margin: 2.5rem 0 0.75rem; line-height: 1.25; }
.article-body h3 { font-size: 1.125rem; font-weight: 600; letter-spacing: -0.015em; margin: 2rem 0 0.5rem; line-height: 1.3; }
.article-body p { margin: 0 0 1.125rem; }
.article-body ul { margin: 0 0 1.25rem; padding-left: 1.25rem; }
.article-body li { margin-bottom: 0.4rem; }
.article-body strong { font-weight: 600; }
.callout { background: var(--warm-soft); border-left: 3px solid var(--warm); padding: 0.875rem 1rem; border-radius: 0 var(--radius-md) var(--radius-md) 0; margin: 1.25rem 0; font-size: 0.9375rem; }

.article-cta { margin: 3rem 0 0; padding: 1.75rem; background: var(--card); border: 1px solid var(--border); border-radius: var(--radius-lg); box-shadow: var(--shadow-subtle); text-align: center; }
.article-cta h2 { font-size: 1.25rem; font-weight: 700; letter-spacing: -0.025em; margin: 0 0 0.625rem; }
.article-cta p { color: var(--muted); margin: 0 0 1.125rem; font-size: 0.9375rem; }
.article-cta .btn { height: 2.75rem; padding: 0 1.5rem; }

.related { max-width: 44rem; margin: 4rem auto 0; padding: 0 1.25rem; }
.related h2 { font-size: 1.125rem; font-weight: 700; letter-spacing: -0.02em; margin: 0 0 1rem; padding-bottom: 0.5rem; border-bottom: 1px solid var(--border); }
.related-list { list-style: none; padding: 0; margin: 0; display: grid; gap: 0.5rem; }
.related-list a { display: flex; flex-direction: column; padding: 0.875rem 1rem; background: var(--card); border: 1px solid var(--border); border-radius: var(--radius-md); transition: border-color .15s, box-shadow .15s; color: var(--fg); }
.related-list a:hover { border-color: var(--warm); box-shadow: var(--shadow-subtle); text-decoration: none; }
.related-cat { font-size: 0.6875rem; font-weight: 600; letter-spacing: 0.1em; text-transform: uppercase; color: var(--warm); margin-bottom: 0.25rem; }
.related-title { font-size: 0.9375rem; font-weight: 500; }

/* footer */
.site-footer { border-top: 1px solid var(--border); margin-top: 4rem; }
.footer-inner { max-width: 64rem; margin: 0 auto; padding: 2rem 1.25rem; display: flex; flex-direction: column; gap: 0.75rem; align-items: center; justify-content: space-between; font-size: 0.875rem; color: var(--muted); text-align: center; }
@media (min-width: 640px) { .footer-inner { flex-direction: row; text-align: left; } }
.footer-links { display: flex; gap: 1.25rem; }
.footer-links a { color: var(--muted); }
.footer-links a:hover { color: var(--fg); text-decoration: none; }