:root {
  --bg: #f4f3f0;
  --bg-accent: #e8e6e1;
  --ink: #141414;
  --muted: #5a5a5a;
  --line: #c8c4bc;
  --max: 880px;
  --font-sans: "IBM Plex Sans", "Source Sans 3", "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", "Consolas", monospace;
  --grid: rgba(20, 20, 20, 0.035);
}

* { box-sizing: border-box; }
html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  line-height: 1.55;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}
body {
  min-height: 100vh;
  background-color: var(--bg);
  background-image:
    linear-gradient(180deg, var(--bg-accent) 0%, transparent 38%),
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: auto, 28px 28px, 28px 28px;
  background-attachment: fixed;
}
a { color: var(--ink); text-underline-offset: 3px; }
a:hover { opacity: 0.72; }

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 1.25rem 4rem; }

nav {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.85rem 1.1rem;
  padding: 1.15rem 0;
  border-bottom: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.02em;
}
nav .brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 600;
  font-size: 0.9rem;
  letter-spacing: 0.04em;
  text-decoration: none;
  text-transform: uppercase;
  margin-right: auto;
  color: var(--ink);
}
nav .brand img { width: 22px; height: 22px; display: block; }
nav a { text-decoration: none; color: var(--muted); }
nav a[aria-current="page"] { color: var(--ink); border-bottom: 1px solid var(--ink); }

.hero {
  padding: 4rem 0 2.75rem;
  border-bottom: 1px solid var(--line);
}
.hero-mark {
  margin: 0 0 1.15rem;
}
.hero-mark img {
  display: block;
  width: 88px;
  height: 88px;
}
.hero h1 {
  font-family: var(--font-mono);
  font-size: clamp(2.2rem, 5.5vw, 3.25rem);
  letter-spacing: -0.04em;
  line-height: 1.05;
  margin: 0 0 1rem;
  font-weight: 600;
}
.hero .tag {
  font-size: 1.02rem;
  color: var(--muted);
  max-width: 34rem;
  margin: 0 0 1.6rem;
}
.hero .cta {
  display: inline-flex;
  gap: 0.65rem;
  flex-wrap: wrap;
}
.btn {
  display: inline-block;
  padding: 0.5rem 0.9rem;
  border: 1px solid var(--ink);
  text-decoration: none;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.02em;
}
.btn.ghost {
  border-color: var(--line);
  color: var(--muted);
}

.section { padding: 2.25rem 0; border-bottom: 1px solid var(--line); }
.section h2 {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin: 0 0 0.85rem;
  font-weight: 600;
}
.section p { color: var(--muted); margin: 0 0 0.75rem; max-width: 38rem; }
.section ul {
  color: var(--muted);
  padding-left: 1.15rem;
  margin: 0.4rem 0 0.75rem;
  max-width: 38rem;
}
.section li { margin: 0.35rem 0; }

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
  margin-top: 1rem;
  font-family: var(--font-mono);
}
th, td {
  text-align: left;
  padding: 0.55rem 0.35rem;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}
th { font-weight: 600; font-size: 0.75rem; letter-spacing: 0.03em; text-transform: uppercase; color: var(--muted); }
td { color: var(--ink); font-size: 0.82rem; }

code, pre {
  font-family: var(--font-mono);
  font-size: 0.82rem;
}
code {
  font-size: 0.85em;
  background: var(--bg-accent);
  padding: 0.08em 0.28em;
  border: 1px solid var(--line);
}
pre {
  background: var(--bg-accent);
  border: 1px solid var(--line);
  padding: 1rem 1.1rem;
  overflow-x: auto;
  line-height: 1.45;
  color: var(--ink);
}
pre code {
  background: none;
  border: none;
  padding: 0;
  font-size: inherit;
}

.diagram {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  line-height: 1.4;
  white-space: pre;
  overflow-x: auto;
}

footer {
  padding: 2rem 0 1rem;
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.02em;
}

footer a { color: var(--muted); }
footer a:hover { color: var(--ink); opacity: 1; }

.note {
  border-left: 2px solid var(--ink);
  padding-left: 0.85rem;
  color: var(--muted);
  font-size: 0.92rem;
  max-width: 38rem;
}

.meta {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--muted);
  letter-spacing: 0.03em;
  text-transform: uppercase;
  margin: 0 0 0.75rem;
}

@media (max-width: 640px) {
  nav { gap: 0.65rem 0.85rem; }
  .hero { padding: 3rem 0 2rem; }
}