:root {
  color-scheme: dark;
  --bg: #0c0f0e;
  --bg-elev: #141a18;
  --text: #e8eee9;
  --muted: #8a968e;
  --accent: #c4f082;
  --accent-ink: #142010;
  --line: #24302a;
  --font: "DM Sans", system-ui, sans-serif;
  --display: "Instrument Serif", Georgia, serif;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  min-height: 100%;
}

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}

.bg-grid {
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(196, 240, 130, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(196, 240, 130, 0.04) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse at 50% 0%, #000 20%, transparent 70%);
}

a { color: inherit; text-decoration: none; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.9rem clamp(1rem, 4vw, 2rem);
  border-bottom: 1px solid var(--line);
  background: rgba(12, 15, 14, 0.92);
  backdrop-filter: blur(10px);
}

.logo {
  font-weight: 700;
  letter-spacing: 0.04em;
  font-size: 1.05rem;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 1.1rem;
  font-size: 0.92rem;
  color: var(--muted);
}

.site-nav > a:hover,
.nav-modules summary:hover {
  color: var(--text);
}

.nav-modules {
  position: relative;
}

.nav-modules summary {
  list-style: none;
  cursor: pointer;
  color: var(--muted);
}

.nav-modules summary::-webkit-details-marker { display: none; }

.nav-modules summary::after {
  content: " ▾";
  font-size: 0.75em;
}

.nav-modules[open] summary {
  color: var(--accent);
}

.nav-modules ul {
  position: absolute;
  right: 0;
  top: calc(100% + 0.55rem);
  margin: 0;
  padding: 0.4rem;
  list-style: none;
  min-width: 14rem;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--bg-elev);
}

.nav-modules a {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
  padding: 0.65rem 0.75rem;
  border-radius: 8px;
}

.nav-modules a:hover {
  background: rgba(196, 240, 130, 0.08);
}

.mod-id {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
}

.mod-name {
  font-size: 0.9rem;
  color: var(--text);
}

main {
  position: relative;
  width: min(52rem, calc(100% - 2rem));
  margin: 0 auto;
  padding: clamp(2.5rem, 8vw, 4.5rem) 0 4rem;
}

.hero .eyebrow {
  margin: 0 0 0.75rem;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
}

.hero h1 {
  margin: 0 0 1rem;
  font-family: var(--display);
  font-weight: 400;
  font-size: clamp(2.4rem, 7vw, 3.75rem);
  line-height: 1.05;
  letter-spacing: -0.02em;
}

.hero h1 em {
  font-style: italic;
  color: var(--accent);
}

.lede {
  margin: 0 0 1.75rem;
  max-width: 36rem;
  color: var(--muted);
  font-size: 1.05rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0.65rem 1.15rem;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.92rem;
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--accent);
  color: var(--accent-ink);
}

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

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

.section {
  margin-top: clamp(3rem, 10vw, 5rem);
  padding-top: 2rem;
  border-top: 1px solid var(--line);
}

.section h2 {
  margin: 0 0 0.5rem;
  font-family: var(--display);
  font-weight: 400;
  font-size: clamp(1.8rem, 4vw, 2.35rem);
}

.section-lead {
  margin: 0 0 1.25rem;
  color: var(--muted);
}

.feature-grid {
  display: grid;
  gap: 1rem;
  margin-top: 1.5rem;
}

@media (min-width: 720px) {
  .feature-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.feature-grid article {
  padding: 1.15rem 1.2rem;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--bg-elev);
}

.feature-grid h3 {
  margin: 0 0 0.4rem;
  font-size: 1rem;
}

.feature-grid p {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.module-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.module-card {
  display: grid;
  gap: 0.25rem;
  padding: 1.2rem 1.25rem;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--bg-elev);
  transition: border-color 160ms ease;
}

.module-card:hover {
  border-color: rgba(196, 240, 130, 0.55);
}

.module-card__id {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
}

.module-card__title {
  font-size: 1.2rem;
  font-weight: 600;
}

.module-card__meta {
  color: var(--muted);
  font-size: 0.88rem;
}

.site-footer {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  justify-content: space-between;
  padding: 1.25rem clamp(1rem, 4vw, 2rem) 2rem;
  border-top: 1px solid var(--line);
  font-size: 0.85rem;
}

.muted { color: var(--muted); }