/* ============================================================
   APPLIED AI FIELD NOTES — Design System (Cyber-Salon)
   Option A: warm editorial serif + electric technical accents
   ============================================================ */

:root {
  /* Canvas & surfaces */
  --bg-canvas:  #0c0d0e;
  --bg-surface: #141618;
  --bg-subtle:  #1c1e22;
  --border-subtle: rgba(255,255,255,0.08);
  --border-strong: rgba(255,255,255,0.16);

  /* Text */
  --text-main:  #f0eee6;
  --text-muted: #8e929a;
  --text-dim:   #5c6068;

  /* Accents */
  --accent-warm:   #d97757;  /* terracotta / amber */
  --accent-glow:   #e28743;
  --accent-edgy:   #7170ff;  /* electric violet */
  --accent-signal: #00d992;  /* pulse green */

  /* Type */
  --font-serif: 'Newsreader', Georgia, serif;
  --font-sans:  'Inter', system-ui, -apple-system, sans-serif;
  --font-mono:  'JetBrains Mono', ui-monospace, monospace;
}

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

html { scroll-behavior: smooth; }

body {
  background-color: var(--bg-canvas);
  color: var(--text-main);
  font-family: var(--font-sans);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  padding: 0 1.5rem;
}

.container { max-width: 1040px; margin: 0 auto; padding: 3rem 0; }
.container.reading { max-width: 780px; }

/* ---------- Header ---------- */
header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: 1.5rem;
  margin-bottom: 3.5rem;
}
.site-title {
  font-family: var(--font-serif);
  font-size: 1.4rem;
  color: var(--text-main);
  text-decoration: none;
  display: flex; align-items: center; gap: 0.5rem;
}
.site-title .pulse {
  display: inline-block; width: 8px; height: 8px; border-radius: 50%;
  background: var(--accent-signal);
  box-shadow: 0 0 8px var(--accent-signal);
  animation: pulse 2.4s ease-in-out infinite;
}
@keyframes pulse {
  0%,100% { opacity: 1; transform: scale(1); }
  50%      { opacity: .55; transform: scale(.82); }
}
nav { display: flex; gap: 1.5rem; }
nav a {
  color: var(--text-muted); text-decoration: none; font-size: 0.9rem;
  transition: color .2s;
}
nav a:hover, nav a.active { color: var(--text-main); }

/* ---------- Channels / Category bar ---------- */
.channels-bar {
  display: flex; gap: 0.75rem; margin-bottom: 3rem;
  overflow-x: auto; padding-bottom: 0.5rem;
}
.channel-pill {
  font-family: var(--font-mono); font-size: 0.8rem;
  padding: 0.4rem 0.8rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: 4px;
  color: var(--text-muted); text-decoration: none; white-space: nowrap;
  transition: all .2s;
}
.channel-pill:hover, .channel-pill.active {
  border-color: var(--accent-warm);
  color: var(--text-main);
  background: var(--bg-subtle);
}
.channel-pill .count { color: var(--text-dim); margin-left: 0.3rem; }

/* ---------- Featured article ---------- */
.featured-article {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  padding: 2.5rem; margin-bottom: 4rem;
  position: relative; overflow: hidden;
}
.featured-article::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 2px;
  background: linear-gradient(90deg, var(--accent-warm), var(--accent-edgy));
}
.meta-tag {
  font-family: var(--font-mono); font-size: 0.75rem;
  text-transform: uppercase; letter-spacing: 0.05em;
  color: var(--accent-warm); margin-bottom: 0.75rem;
  display: flex; align-items: center; gap: 0.5rem; flex-wrap: wrap;
}
.article-title {
  font-family: var(--font-serif); font-size: 2.25rem; font-weight: 400;
  line-height: 1.2; margin-bottom: 1rem; letter-spacing: -0.01em;
}
.article-title a { color: var(--text-main); text-decoration: none; }
.article-excerpt {
  color: var(--text-muted); font-size: 1.05rem; line-height: 1.6;
  margin-bottom: 1.5rem; max-width: 800px;
}

/* ---------- Grid ---------- */
.grid-section-title {
  font-family: var(--font-mono); font-size: 0.85rem; color: var(--text-dim);
  border-bottom: 1px solid var(--border-subtle); padding-bottom: 0.5rem;
  margin-bottom: 2rem; display: flex; justify-content: space-between;
}
.articles-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem; margin-bottom: 4rem;
}
.grid-card {
  background: var(--bg-surface); border: 1px solid var(--border-subtle);
  border-radius: 6px; padding: 1.5rem;
  display: flex; flex-direction: column; justify-content: space-between;
  transition: border-color .2s, transform .2s;
}
.grid-card:hover { border-color: var(--border-strong); transform: translateY(-2px); }
.card-title {
  font-family: var(--font-serif); font-size: 1.35rem; font-weight: 400;
  line-height: 1.3; margin-bottom: 0.75rem;
}
.card-title a { color: var(--text-main); text-decoration: none; }
.card-desc { color: var(--text-muted); font-size: 0.9rem; line-height: 1.5; margin-bottom: 1.25rem; }
.card-footer {
  font-family: var(--font-mono); font-size: 0.75rem; color: var(--text-dim);
  display: flex; justify-content: space-between; align-items: center;
  border-top: 1px solid var(--border-subtle); padding-top: 0.75rem;
}

/* ---------- System spec / telemetry ---------- */
.system-spec, .telemetry-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-left: 2px solid var(--accent-edgy);
  padding: 1.25rem; font-family: var(--font-mono); font-size: 0.8rem;
  color: var(--text-muted); margin: 2rem 0; border-radius: 0 4px 4px 0;
}
.telemetry-header {
  color: var(--accent-edgy); margin-bottom: 0.75rem;
  display: flex; justify-content: space-between;
  border-bottom: 1px solid var(--border-subtle); padding-bottom: 0.4rem;
}
.telemetry-grid {
  display: grid; grid-template-columns: repeat(2, 1fr);
  gap: 0.5rem; margin-top: 0.5rem;
}
.telemetry-grid strong { color: var(--text-main); }

/* ---------- Article prose ---------- */
.article-header { margin-bottom: 3rem; }
.meta-channel {
  font-family: var(--font-mono); font-size: 0.8rem;
  color: var(--accent-warm); text-transform: uppercase;
  letter-spacing: 0.05em; margin-bottom: 0.75rem;
}
.post-title {
  font-family: var(--font-serif); font-size: 2.75rem; font-weight: 400;
  line-height: 1.15; letter-spacing: -0.02em; margin-bottom: 1.25rem;
}
.post-metadata {
  display: flex; gap: 1.5rem; flex-wrap: wrap;
  font-family: var(--font-mono); font-size: 0.8rem; color: var(--text-dim);
  border-bottom: 1px solid var(--border-subtle); padding-bottom: 1.5rem;
}
.prose p { font-size: 1.05rem; margin-bottom: 1.5rem; }
.prose h2 {
  font-family: var(--font-serif); font-size: 1.75rem; font-weight: 400;
  margin: 2.5rem 0 1rem 0;
}
.prose blockquote {
  border-left: 2px solid var(--accent-warm); padding-left: 1.25rem;
  margin: 2rem 0; font-family: var(--font-serif); font-style: italic;
  font-size: 1.2rem; color: var(--text-muted);
}
.prose a { color: var(--accent-glow); }

/* ---------- Code ---------- */
.code-block {
  background: var(--bg-surface); border: 1px solid var(--border-subtle);
  border-radius: 6px; margin: 2rem 0; overflow: hidden;
}
.code-header {
  background: var(--bg-subtle); padding: 0.5rem 1rem;
  display: flex; justify-content: space-between;
  font-family: var(--font-mono); font-size: 0.75rem; color: var(--text-dim);
  border-bottom: 1px solid var(--border-subtle);
}
pre {
  padding: 1.25rem; font-family: var(--font-mono); font-size: 0.85rem;
  color: var(--text-muted); overflow-x: auto; line-height: 1.5;
}
pre code .k { color: var(--accent-edgy); }
pre code .f { color: var(--accent-signal); }
pre code .s { color: var(--accent-warm); }
pre code .c { color: var(--text-dim); font-style: italic; }

/* ---------- Figures ---------- */
.figure-container { margin: 2.5rem 0; }
.figure-box {
  width: 100%; min-height: 300px;
  background: var(--bg-surface); border: 1px solid var(--border-subtle);
  border-radius: 6px; display: flex; align-items: center; justify-content: center;
  overflow: hidden;
}
.figure-box img { width: 100%; height: 100%; object-fit: cover; display: block; }
figcaption {
  font-family: var(--font-mono); font-size: 0.75rem;
  color: var(--text-dim); margin-top: 0.5rem; text-align: center;
}

/* Diagram mocks (pure CSS/SVG-ready) */
.diagram-mock { display: flex; gap: 1rem; align-items: center; flex-wrap: wrap; padding: 1rem; }
.node {
  background: var(--bg-subtle); border: 1px solid var(--border-strong);
  padding: 0.75rem 1.25rem; border-radius: 4px;
  font-family: var(--font-mono); font-size: 0.75rem; text-align: center;
}
.node.active { border-color: var(--accent-signal); box-shadow: 0 0 10px rgba(0,217,146,0.2); }
.node-arrow { color: var(--accent-edgy); font-family: var(--font-mono); }

/* ---------- Footer ---------- */
footer {
  border-top: 1px solid var(--border-subtle); padding-top: 2rem;
  margin-top: 4rem; display: flex; justify-content: space-between;
  flex-wrap: wrap; gap: 0.5rem;
  font-family: var(--font-mono); font-size: 0.8rem; color: var(--text-dim);
}
footer a { color: var(--text-dim); }
footer a:hover { color: var(--accent-warm); }

/* ---------- Back link ---------- */
.back-link {
  font-family: var(--font-mono); font-size: 0.8rem; color: var(--text-muted);
  text-decoration: none; display: flex; align-items: center; gap: 0.4rem;
}
.back-link:hover { color: var(--accent-warm); }

/* ---------- Responsive ---------- */
@media (max-width: 640px) {
  .post-title { font-size: 2rem; }
  .article-title { font-size: 1.7rem; }
  .featured-article, .grid-card { padding: 1.5rem; }
  .telemetry-grid { grid-template-columns: 1fr; }
  nav { gap: 1rem; }
}