/* ── Custom Properties ───────────────────────────────────── */
:root {
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'SF Mono', 'Fira Code', ui-monospace, Menlo, Monaco, monospace;
  --text: #111;
  --text-2: #444;
  --text-3: #888;
  --border: #e8e8e8;
  --border-2: #f0f0f0;
  --bg: #fff;
  --bg-2: #fafafa;
  --bg-3: #f4f4f4;
}

/* ── Reset ───────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }
[hidden] { display: none !important; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  margin: 0;
  padding: 0;
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ── Layout ──────────────────────────────────────────────── */
.container {
  max-width: 884px;
  margin: 0 auto;
  padding: 0 32px;
}

/* ── Typography ──────────────────────────────────────────── */
h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.15;
  margin: 0 0 0.5rem;
  color: var(--text);
}
h2 {
  font-size: 0.68rem;
  font-weight: 600;
  color: var(--text-3);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin: 3rem 0 1.25rem;
}
h3 {
  font-size: 0.9375rem;
  font-weight: 600;
  margin: 0 0 0.25rem;
  color: var(--text);
}
p {
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--text-2);
  margin: 0 0 1em;
}
a { color: inherit; }
strong { color: var(--text); font-weight: 600; }

code {
  font-family: var(--font-mono);
  background: var(--bg-3);
  border: 1px solid var(--border);
  padding: 1px 5px;
  font-size: 0.82em;
  border-radius: 3px;
}
pre {
  overflow: auto;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg-2);
}
pre code { background: none; border: none; padding: 0; font-size: 0.85em; }

/* ── Site nav ────────────────────────────────────────────── */
.site-nav {
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  z-index: 100;
}
.nav-inner {
  max-width: 884px;
  margin: 0 auto;
  padding: 0 32px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-left {
  display: flex;
  align-items: center;
  gap: 32px;
}
.site-nav .brand {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  letter-spacing: -0.03em;
}
.nav-links {
  display: flex;
  gap: 2px;
}
.nav-links a {
  font-size: 0.875rem;
  color: var(--text-3);
  text-decoration: none;
  padding: 5px 10px;
  border-radius: 5px;
  transition: color 0.1s, background 0.1s;
}
.nav-links a:hover { color: var(--text); background: var(--bg-3); }
.nav-auth { display: flex; gap: 8px; align-items: center; }

/* ── Buttons ─────────────────────────────────────────────── */
.btn {
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-weight: 500;
  padding: 6px 14px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  cursor: pointer;
  color: var(--text-2);
  text-decoration: none;
  display: inline-block;
  transition: border-color 0.1s, color 0.1s, background 0.1s;
  line-height: 1.5;
}
.btn:hover { border-color: #bbb; color: var(--text); }
.btn-primary { background: var(--text); color: #fff; border-color: var(--text); }
.btn-primary:hover { background: #333; border-color: #333; color: #fff; }

/* ── Forms ───────────────────────────────────────────────── */
.form-group { margin-bottom: 20px; }
.form-group label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text);
  margin-bottom: 6px;
}
.form-group input {
  display: block;
  width: 100%;
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  padding: 9px 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  outline: none;
  transition: border-color 0.15s, box-shadow 0.15s;
  color: var(--text);
}
.form-group input:focus {
  border-color: var(--text);
  box-shadow: 0 0 0 3px rgba(0,0,0,0.06);
}
.form-error { font-size: 0.8125rem; color: #c00; margin-top: 6px; }

/* ── Utilities ───────────────────────────────────────────── */
.muted { color: var(--text-3); font-size: 0.875rem; }
hr { border: none; border-top: 1px solid var(--border); margin: 2.5em 0; }

/* ── Mobile base ─────────────────────────────────────────── */
@media (max-width: 640px) {
  .container { padding: 0 20px; }

  .nav-inner { padding: 0 20px; }
  .nav-links { display: none; }

  h1 { font-size: 1.625rem; }
}