/* ---------- Tokens ---------- */

:root {
  --bg-deep:   #0a0e1a;
  --bg-card:   #131825;
  --bg-code:   #0d111c;
  --border:    #1f2937;
  --border-soft: #182030;
  --fg:        #e5e7eb;
  --fg-muted:  #9ca3af;
  --fg-dim:    #6b7280;
  --accent:    #3df97f;          /* terminal green */
  --accent-dim:#1d8c47;
  --accent-2:  #ff6b35;          /* signal orange — used sparingly */
  --warn:      #fbbf24;

  --font-sans: ui-sans-serif, system-ui, "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mono: ui-monospace, "SF Mono", Menlo, Consolas, "DejaVu Sans Mono", monospace;
  --radius:    8px;
  --max:       1080px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg-deep);
  color: var(--fg);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

/* Background — subtle starfield */
body {
  background-image:
    radial-gradient(1px 1px at 17% 23%,  #ffffff14 50%, transparent 51%),
    radial-gradient(1px 1px at 73% 14%,  #ffffff10 50%, transparent 51%),
    radial-gradient(1px 1px at 38% 67%,  #ffffff14 50%, transparent 51%),
    radial-gradient(1px 1px at 91% 41%,  #ffffff10 50%, transparent 51%),
    radial-gradient(1px 1px at 9% 81%,   #ffffff14 50%, transparent 51%),
    radial-gradient(1px 1px at 56% 88%,  #ffffff10 50%, transparent 51%),
    radial-gradient(1200px 600px at 50% -10%, #1a2034 0%, transparent 70%);
}

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px dotted var(--accent-dim);
}
a:hover { border-bottom-style: solid; }

code, pre, .mono { font-family: var(--font-mono); }

code {
  background: var(--bg-code);
  padding: 0.1em 0.35em;
  border-radius: 4px;
  border: 1px solid var(--border-soft);
  font-size: 0.92em;
}

pre {
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
  overflow-x: auto;
  line-height: 1.45;
  font-size: 0.88em;
}
pre code { background: none; border: none; padding: 0; }

.prompt { color: var(--accent); user-select: none; }
.comment { color: var(--fg-dim); }
.kw { color: var(--accent-2); }

/* ---------- Layout ---------- */

.wrap {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 24px;
}

nav.top {
  border-bottom: 1px solid var(--border);
  padding: 16px 0;
  background: rgba(10, 14, 26, 0.85);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 10;
}
nav.top .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
nav.top .brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 1.05rem;
  letter-spacing: 0.04em;
  color: var(--fg);
  border-bottom: none;
}
nav.top .brand svg {
  width: 28px;
  height: 28px;
  color: var(--accent);
}
nav.top .links { display: flex; gap: 20px; }
nav.top .links a {
  color: var(--fg-muted);
  border-bottom: none;
  font-size: 0.95rem;
}
nav.top .links a:hover { color: var(--accent); }

/* Hero */
.hero {
  padding: 96px 0 64px;
  text-align: center;
}
.hero .logo {
  width: 140px;
  height: 140px;
  margin: 0 auto 28px;
  color: var(--accent);
  filter: drop-shadow(0 0 24px rgba(61, 249, 127, 0.18));
}
.hero h1 {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: clamp(2.5rem, 6vw, 4.25rem);
  letter-spacing: -0.01em;
  margin: 0 0 16px;
  line-height: 1.05;
}
.hero h1 .accent { color: var(--accent); }
.hero .tagline {
  font-size: clamp(1.05rem, 2.2vw, 1.25rem);
  color: var(--fg-muted);
  max-width: 700px;
  margin: 0 auto 40px;
}
.hero .cta {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 22px;
  border: 1px solid var(--accent);
  border-radius: var(--radius);
  background: rgba(61, 249, 127, 0.07);
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.95rem;
  margin: 0 6px 8px;
}
.hero .cta:hover { background: rgba(61, 249, 127, 0.14); }
.hero .cta.secondary {
  border-color: var(--border);
  color: var(--fg);
  background: var(--bg-card);
}
.hero .cta.secondary:hover { border-color: var(--fg-muted); }

.hero .meta {
  margin-top: 32px;
  display: flex;
  justify-content: center;
  gap: 18px;
  flex-wrap: wrap;
  color: var(--fg-dim);
  font-family: var(--font-mono);
  font-size: 0.82rem;
}
.hero .meta .pill {
  border: 1px solid var(--border);
  padding: 4px 10px;
  border-radius: 999px;
}
.hero .meta .pill .dot {
  display: inline-block;
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--accent);
  margin-right: 6px;
  vertical-align: middle;
}

/* Section base */
section {
  padding: 56px 0;
  border-top: 1px solid var(--border-soft);
}
section h2 {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  margin: 0 0 8px;
  color: var(--fg);
}
section h2 .lead {
  color: var(--accent);
  margin-right: 8px;
}
section .sub {
  color: var(--fg-muted);
  margin: 0 0 28px;
  max-width: 700px;
}

/* Three columns: Sim / RF / Hardware */
.paths {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}
@media (max-width: 760px) {
  .paths { grid-template-columns: 1fr; }
}
.path-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  transition: border-color 0.15s ease;
}
.path-card:hover { border-color: var(--accent-dim); }
.path-card h3 {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  margin: 0 0 6px;
  color: var(--accent);
  letter-spacing: 0.02em;
}
.path-card .badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  background: rgba(61, 249, 127, 0.1);
  color: var(--accent);
  border: 1px solid var(--accent-dim);
  border-radius: 4px;
  padding: 2px 6px;
  margin-bottom: 12px;
}
.path-card p {
  color: var(--fg-muted);
  font-size: 0.95rem;
  margin: 0 0 14px;
}
.path-card pre {
  margin: 0;
  font-size: 0.78rem;
}

/* Feature grid */
.features {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}
@media (max-width: 760px) { .features { grid-template-columns: 1fr; } }
.feature {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
}
.feature h4 {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  margin: 0 0 8px;
  color: var(--accent);
}
.feature p {
  color: var(--fg-muted);
  font-size: 0.92rem;
  margin: 0;
}

/* Curriculum table */
table.curriculum {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.94rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
table.curriculum th,
table.curriculum td {
  text-align: left;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border-soft);
}
table.curriculum th {
  background: rgba(255,255,255,0.02);
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--fg-muted);
  font-weight: 600;
}
table.curriculum td.lesson-num {
  font-family: var(--font-mono);
  color: var(--accent);
  width: 4em;
}
table.curriculum td.tag-yes {
  color: var(--accent);
  font-family: var(--font-mono);
}
table.curriculum td.tag-partial {
  color: var(--warn);
  font-family: var(--font-mono);
}
table.curriculum tr:last-child td { border-bottom: none; }

/* Architecture */
.arch {
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  overflow-x: auto;
}
.arch pre {
  background: none;
  border: none;
  padding: 0;
  color: var(--fg-muted);
  font-size: 0.80rem;
  line-height: 1.4;
}

/* Safety callout */
.callout {
  border: 1px solid var(--accent-2);
  background: rgba(255, 107, 53, 0.06);
  border-radius: var(--radius);
  padding: 18px 22px;
}
.callout h3 {
  font-family: var(--font-mono);
  margin: 0 0 8px;
  color: var(--accent-2);
  font-size: 1rem;
}
.callout p { margin: 0 0 6px; color: var(--fg); }
.callout p:last-child { margin-bottom: 0; }

/* Footer */
footer {
  border-top: 1px solid var(--border);
  padding: 32px 0 48px;
  margin-top: 32px;
  color: var(--fg-dim);
  font-size: 0.88rem;
}
footer .wrap {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
}
footer .left { display: flex; align-items: center; gap: 10px; }
footer .left svg {
  width: 18px; height: 18px;
  color: var(--accent-dim);
}
footer a { color: var(--fg-muted); border-bottom-color: var(--border); }

/* Small helpers */
ul.bullets { padding-left: 1.2em; color: var(--fg-muted); }
ul.bullets li { margin-bottom: 6px; }
ul.bullets li::marker { color: var(--accent); }