:root {
  --ink-deep: #0f2a43;
  --ink-mid: #163a5c;
  --line: #4f88b3;
  --line-bright: #8fd3ff;
  --paper: #eaf2f8;
  --amber: #ffb000;
  --muted: #9db8cf;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--ink-deep);
  color: var(--paper);
  font-family: 'IBM Plex Sans', sans-serif;
  line-height: 1.55;
  position: relative;
  overflow-x: hidden;
}

.grid-overlay {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background-image:
    linear-gradient(to right, rgba(143, 211, 255, 0.05) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(143, 211, 255, 0.05) 1px, transparent 1px);
  background-size: 40px 40px;
}

.eyebrow {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  color: var(--line-bright);
  margin-bottom: 0.9rem;
}

header.site-header {
  position: relative;
  z-index: 1;
  max-width: 760px;
  margin: 0 auto;
  padding: 6rem 1.5rem 4rem;
}

h1 {
  font-family: 'IBM Plex Mono', monospace;
  font-weight: 600;
  font-size: clamp(2.1rem, 5vw, 3.2rem);
  line-height: 1.12;
  margin: 0 0 1.5rem;
  letter-spacing: -0.01em;
}

.lede {
  font-size: 1.08rem;
  color: var(--muted);
  max-width: 56ch;
  margin: 0 0 2.2rem;
}

.cta-row { display: flex; gap: 0.9rem; flex-wrap: wrap; }

.btn {
  display: inline-block;
  padding: 0.75rem 1.4rem;
  border-radius: 2px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.85rem;
  text-decoration: none;
  border: 1px solid var(--line);
  transition: border-color 0.15s ease, background 0.15s ease;
}

.btn-primary {
  background: var(--amber);
  color: var(--ink-deep);
  border-color: var(--amber);
  font-weight: 600;
}
.btn-primary:hover { background: #ffc233; }

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

main {
  position: relative;
  z-index: 1;
  max-width: 980px;
  margin: 0 auto;
  padding: 0 1.5rem 5rem;
}

section { margin-bottom: 5rem; }

h2 {
  font-family: 'IBM Plex Mono', monospace;
  font-weight: 500;
  font-size: 1.5rem;
  margin: 0 0 2rem;
}

.diagram-section {
  border-top: 1px solid rgba(143, 211, 255, 0.18);
  padding-top: 3.5rem;
}

.diagram {
  width: 100%;
  height: auto;
  overflow: visible;
}

.node rect {
  fill: var(--ink-mid);
  stroke: var(--line);
  stroke-width: 1;
}
.node-accent rect {
  stroke: var(--line-bright);
  stroke-width: 1.5;
}
.node-dashed rect {
  fill: transparent;
  stroke: var(--muted);
  stroke-dasharray: 3 3;
}

.node-title {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 14px;
  font-weight: 600;
  fill: var(--paper);
  text-anchor: middle;
}
.node-title-sm {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px;
  font-weight: 600;
  fill: var(--muted);
  text-anchor: middle;
}
.node-sub {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px;
  fill: var(--muted);
  text-anchor: middle;
}

.conn { stroke: var(--line); stroke-width: 1.25; }
.conn.dashed { stroke: var(--muted); stroke-dasharray: 4 3; }
.arrow { fill: var(--line-bright); }

.diagram-caption {
  font-size: 0.9rem;
  color: var(--muted);
  max-width: 60ch;
  margin-top: 1.8rem;
}

.stack-section {
  border-top: 1px solid rgba(143, 211, 255, 0.18);
  padding-top: 3.5rem;
}

.stack-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.8rem 2.5rem;
  margin: 0;
}

.stack-item dt {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.95rem;
  color: var(--line-bright);
  margin-bottom: 0.4rem;
}
.stack-item dd {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.site-footer {
  position: relative;
  z-index: 1;
  border-top: 1px solid rgba(143, 211, 255, 0.18);
  text-align: center;
  padding: 2rem 1.5rem 3rem;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.8rem;
  color: var(--muted);
}
.site-footer a { color: var(--line-bright); }

@media (max-width: 640px) {
  .stack-list { grid-template-columns: 1fr; }
  header.site-header { padding: 4rem 1.25rem 3rem; }
}