/* signal.primals.eco — billboard CSS */
/* Minimal, fast, readable. No frameworks. */

:root {
  --bg: #0a0a0a;
  --fg: #e8e8e8;
  --accent: #ff6b35;
  --accent-dim: #cc5529;
  --link: #5dade2;
  --link-visited: #a78bfa;
  --code-bg: #1a1a2e;
  --border: #333;
  --table-stripe: #111;
  --green: #2ecc71;
  --red: #e74c3c;
  --yellow: #f1c40f;
  --max-width: 900px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 16px; scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.7;
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--accent);
  color: #fff;
  padding: 8px;
  z-index: 100;
}
.skip-link:focus { top: 0; }

/* ── Header ── */
.site-header {
  border-bottom: 2px solid var(--accent);
  padding: 1rem 2rem;
  position: sticky;
  top: 0;
  background: var(--bg);
  z-index: 50;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 2rem;
  max-width: var(--max-width);
  margin: 0 auto;
  flex-wrap: wrap;
}

.site-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent);
  text-decoration: none;
  font-family: 'Courier New', monospace;
}

.site-nav ul {
  display: flex;
  list-style: none;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.site-nav a {
  color: var(--fg);
  text-decoration: none;
  font-size: 0.85rem;
  opacity: 0.8;
}
.site-nav a:hover { opacity: 1; color: var(--accent); }

/* ── Main ── */
.site-main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem;
}

/* ── Billboard ── */
.billboard h2 {
  font-size: 1.8rem;
  margin: 3rem 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
  color: var(--accent);
}

.billboard h3 {
  font-size: 1.3rem;
  margin: 2rem 0 0.8rem;
  color: var(--fg);
}

.billboard h4 {
  font-size: 1.1rem;
  margin: 1.5rem 0 0.5rem;
  color: var(--accent-dim);
}

.billboard h5, .billboard h6 {
  font-size: 1rem;
  margin: 1rem 0 0.5rem;
}

.billboard p {
  margin: 0.8rem 0;
}

.billboard strong {
  color: #fff;
}

/* ── Links ── */
a { color: var(--link); }
a:visited { color: var(--link-visited); }
a:hover { text-decoration: underline; }

/* ── Code ── */
code {
  background: var(--code-bg);
  padding: 0.15em 0.4em;
  border-radius: 3px;
  font-size: 0.9em;
  font-family: 'Courier New', Consolas, monospace;
}

pre {
  background: var(--code-bg);
  padding: 1rem;
  border-radius: 4px;
  overflow-x: auto;
  margin: 1rem 0;
  border: 1px solid var(--border);
}
pre code { background: none; padding: 0; }

/* ── Tables ── */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.85rem;
}

th {
  background: var(--code-bg);
  padding: 0.6rem 0.8rem;
  text-align: left;
  border-bottom: 2px solid var(--accent);
  font-weight: 600;
}

td {
  padding: 0.5rem 0.8rem;
  border-bottom: 1px solid var(--border);
}

tr:nth-child(even) td { background: var(--table-stripe); }

/* ── Lists ── */
ul, ol {
  margin: 0.5rem 0 0.5rem 1.5rem;
}
li { margin: 0.3rem 0; }

/* ── Blockquotes ── */
blockquote {
  border-left: 3px solid var(--accent);
  padding: 0.5rem 1rem;
  margin: 1rem 0;
  font-style: italic;
  color: #bbb;
}

/* ── Horizontal rules ── */
hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 3rem 0;
}

/* ── Footer ── */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 2rem;
  margin-top: 4rem;
  text-align: center;
  font-size: 0.8rem;
  color: #888;
}
.site-footer a { color: var(--link); }

/* ── Signal exploration graph ── */
#signal-exploration {
  min-height: 400px;
  background: var(--code-bg);
  border-radius: 4px;
  border: 1px solid var(--border);
}

/* ── Responsive ── */
@media (max-width: 700px) {
  .site-main { padding: 1rem; }
  .site-header { padding: 0.8rem 1rem; }
  .site-nav { flex-direction: column; gap: 0.5rem; }
  .billboard h2 { font-size: 1.4rem; }
  table { font-size: 0.75rem; }
  th, td { padding: 0.3rem 0.5rem; }
}