/* Shared stylesheet for the /blog pages.
   Tokens, nav, buttons and footer are copied verbatim from public/index.html
   so the blog matches the landing page exactly — see that file if the two
   ever need to be brought back in sync. */

:root {
  /* Brand palette — shared with index.html and demo.html */
  --bg: #0f1115;
  --card: #1a1d24;
  --border: #2b2f3a;
  --accent: #6ee7b7;
  --accent2: #60a5fa;
  --text: #e5e7eb;
  --muted: #9aa1ad;

  /* Derived surfaces */
  --sunken: #0d0f13;
  --raised: #222630;
  --border-soft: #21252e;
  --faint: #6b7280;

  /* 4px spacing scale */
  --s1: 4px;  --s2: 8px;  --s3: 12px; --s4: 16px;
  --s6: 24px; --s8: 32px; --s12: 48px; --s16: 64px;
  --s24: 96px;

  --r-control: 8px;
  --r-card: 12px;
  --h-control: 42px;

  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.wrap { max-width: 1080px; margin: 0 auto; padding: 0 var(--s6); }

/* ---------- Logo ---------- */
.logo { --logo-h: 30px; display: block; height: var(--logo-h); flex: none; }
.logo img { display: block; height: 100%; width: auto; }

/* ---------- Nav ---------- */
nav {
  border-bottom: 1px solid var(--border-soft);
  position: sticky;
  top: 0;
  background: rgba(15, 17, 21, .82);
  backdrop-filter: blur(10px);
  z-index: 50;
}
nav .wrap {
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--s6);
}
.nav-links { display: flex; align-items: center; gap: var(--s6); }
.nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: color .15s;
}
.nav-links a:hover { color: var(--text); }
.nav-links a[aria-current="page"] { color: var(--text); }
.nav-links a.btn-primary,
.nav-links a.btn-primary:hover { color: #0d1117; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--s2);
  height: var(--h-control);
  padding: 0 20px;
  border-radius: var(--r-control);
  font-size: 14.5px;
  font-weight: 600;
  text-decoration: none;
  border: 1px solid transparent;
  cursor: pointer;
  font-family: inherit;
  transition: background .15s, border-color .15s, color .15s;
  white-space: nowrap;
}
.btn-primary { background: var(--accent); color: #0d1117; }
.btn-primary:hover { background: #8af0c8; }
.btn-secondary { background: var(--raised); color: var(--text); border-color: var(--border); }
.btn-secondary:hover { background: #2a2f3a; border-color: #3a4150; }
.btn-sm { height: 34px; padding: 0 14px; font-size: 13.5px; }
.btn:focus-visible { outline: none; box-shadow: 0 0 0 3px rgba(96,165,250,.35); }

/* ---------- Sections / type scale ---------- */
section { padding: var(--s16) 0; }
section + section { border-top: 1px solid var(--border-soft); }

.eyebrow {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .09em;
  color: var(--accent);
  margin: 0 0 var(--s3);
}
h1 {
  font-size: clamp(30px, 4.6vw, 44px);
  font-weight: 600;
  letter-spacing: -.03em;
  line-height: 1.15;
  margin: 0 0 var(--s4);
}
h2 {
  font-size: clamp(22px, 2.8vw, 28px);
  font-weight: 600;
  letter-spacing: -.02em;
  line-height: 1.25;
  margin: var(--s8) 0 var(--s4);
}
.lead {
  font-size: 17px;
  color: var(--muted);
  margin: 0 0 var(--s8);
  max-width: 68ch;
  line-height: 1.65;
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  font-weight: 500;
  color: var(--muted);
  background: var(--sunken);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 4px 12px;
}

/* ---------- Blog index list ---------- */
.blog-list { display: grid; gap: var(--s4); max-width: 68ch; }
.blog-card {
  display: block;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--r-card);
  padding: var(--s6);
  text-decoration: none;
  color: inherit;
  transition: border-color .15s;
}
.blog-card:hover { border-color: #39404e; }
.blog-date {
  display: block;
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: .03em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 var(--s2);
}
.blog-card h3 {
  font-size: 19px;
  font-weight: 600;
  letter-spacing: -.015em;
  line-height: 1.35;
  color: var(--text);
  margin: 0 0 var(--s2);
}
.blog-excerpt { font-size: 14.5px; color: var(--muted); line-height: 1.6; margin: 0; }

/* ---------- Article ---------- */
.article-header { max-width: 68ch; }
.article-meta {
  display: flex;
  align-items: center;
  gap: var(--s3);
  flex-wrap: wrap;
  margin-bottom: var(--s4);
}
.article-tags { display: flex; gap: var(--s2); flex-wrap: wrap; }

.article-body { max-width: 68ch; font-size: 16.5px; line-height: 1.75; color: var(--text); }
.article-body p { margin: 0 0 var(--s6); }
.article-body h2 { font-size: 23px; }
.article-body h2:first-child { margin-top: 0; }
.article-body ul {
  margin: 0 0 var(--s6);
  padding-left: 1.3em;
  display: grid;
  gap: var(--s3);
}
.article-body li { line-height: 1.65; }
.article-body strong { color: var(--text); font-weight: 600; }
.article-body a { color: var(--accent2); text-decoration: underline; text-underline-offset: 2px; }
.article-body a:hover { color: var(--text); }
.article-body code {
  font-family: var(--mono);
  font-size: .88em;
  background: var(--sunken);
  border: 1px solid var(--border-soft);
  border-radius: 4px;
  padding: 1px 6px;
  color: var(--accent);
}

.article-footer-note {
  max-width: 68ch;
  margin-top: var(--s8);
  padding-top: var(--s6);
  border-top: 1px solid var(--border-soft);
  font-size: 14.5px;
  color: var(--muted);
}
.article-footer-note a { color: var(--muted); text-decoration: underline; text-underline-offset: 2px; transition: color .15s; }
.article-footer-note a:hover { color: var(--text); }

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13.5px;
  font-weight: 500;
  color: var(--muted);
  text-decoration: none;
  margin-bottom: var(--s6);
  transition: color .15s;
}
.back-link:hover { color: var(--text); }

/* ---------- Footer ---------- */
footer { border-top: 1px solid var(--border-soft); padding: var(--s12) 0; }
footer .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--s6);
  flex-wrap: wrap;
}
.footer-links { display: flex; align-items: center; gap: var(--s6); flex-wrap: wrap; }
.footer-links a { color: var(--muted); text-decoration: none; font-size: 13.5px; transition: color .15s; }
.footer-links a:hover { color: var(--text); }
.footer-note { color: var(--faint); font-size: 13px; }

@media (max-width: 720px) {
  section { padding: var(--s12) 0; }
  .nav-links .nav-hide { display: none; }
  footer .wrap { flex-direction: column; align-items: flex-start; gap: var(--s3); }
}