/* ============================================================
   PathViz 3.0 — Part 04 design system
   Aesthetic: network operations console, after hours.
   Typography: IBM Plex Sans (body) + IBM Plex Mono (data/code)
   Signature: cable-teal on deep navy, sharp hairlines, no soft edges.

   All tokens use var(--pv-*, fallback) so Part 00's theme.css can override.
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=IBM+Plex+Mono:wght@400;500;600&family=IBM+Plex+Sans:wght@300;400;500;600;700&display=swap');

:root {
  /* --- color tokens (dark is default) --- */
  --pv-bg:           var(--pv-bg,         #0a1420);
  --pv-surface:      var(--pv-surface,    #111d2d);
  --pv-surface-2:    var(--pv-surface-2,  #162638);
  --pv-surface-hi:   var(--pv-surface-hi, #1b2e45);
  --pv-border:       var(--pv-border,     #1e3148);
  --pv-border-hi:    var(--pv-border-hi,  #2a4261);
  --pv-text:         var(--pv-text,       #d8e4f4);
  --pv-text-muted:   var(--pv-text-muted, #7a92aa);
  --pv-text-dim:     var(--pv-text-dim,   #556b82);

  /* Signal palette — ties to Mission Control traffic lights */
  --pv-green:        #34d399;
  --pv-amber:        #fbbf24;
  --pv-red:          #f87171;
  --pv-yellow-soft:  #eab308;

  /* Signature — cable-teal (submarine cable blue-green) */
  --pv-accent:       #2dd4bf;
  --pv-accent-dim:   #0d9488;
  --pv-accent-glow:  rgba(45, 212, 191, 0.18);

  /* Narrator-amber for cinema style */
  --pv-cinema:       #f59e0b;
  --pv-cinema-glow:  rgba(245, 158, 11, 0.14);

  /* Typography */
  --pv-sans:         'IBM Plex Sans', system-ui, sans-serif;
  --pv-mono:         'IBM Plex Mono', ui-monospace, 'Cascadia Code', monospace;
  --pv-size-micro:   11px;
  --pv-size-small:   13px;
  --pv-size-body:    14px;
  --pv-size-read:    15px;
  --pv-size-h3:      17px;
  --pv-size-h2:      22px;
  --pv-size-h1:      28px;

  /* Rhythm */
  --pv-u:            4px;      /* base spacing unit */
  --pv-hairline:     1px solid var(--pv-border);
  --pv-hairline-hi:  1px solid var(--pv-border-hi);
}

/* Light theme — flip the palette on <html data-theme="light"> */
html[data-theme="light"] {
  --pv-bg:           #f6f4ef;
  --pv-surface:      #ffffff;
  --pv-surface-2:    #f0ece4;
  --pv-surface-hi:   #e8e3d8;
  --pv-border:       #d6cfc0;
  --pv-border-hi:    #a99e86;
  --pv-text:         #1c2430;
  --pv-text-muted:   #5a6372;
  --pv-text-dim:     #8b93a1;
  --pv-accent:       #0d9488;
  --pv-accent-dim:   #14b8a6;
  --pv-accent-glow:  rgba(13, 148, 136, 0.12);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--pv-bg);
  color: var(--pv-text);
  font-family: var(--pv-sans);
  font-size: var(--pv-size-body);
  line-height: 1.55;
  font-feature-settings: "tnum" 1, "ss01" 1;
  -webkit-font-smoothing: antialiased;
}

/* Subtle starfield / grid atmosphere behind the content */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(circle 1px at 20% 30%, var(--pv-border) 1px, transparent 1px),
    radial-gradient(circle 1px at 70% 60%, var(--pv-border) 1px, transparent 1px),
    radial-gradient(circle 1px at 40% 80%, var(--pv-border) 1px, transparent 1px),
    radial-gradient(circle 1px at 90% 20%, var(--pv-border) 1px, transparent 1px);
  background-size: 600px 600px;
  opacity: 0.35;
  pointer-events: none;
  z-index: 0;
}

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

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

/* ============================================================
   Header pill strip
   ============================================================ */
.pv-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  gap: calc(var(--pv-u) * 4);
  padding: calc(var(--pv-u) * 3) calc(var(--pv-u) * 5);
  border-bottom: var(--pv-hairline);
  background: color-mix(in srgb, var(--pv-bg) 88%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.pv-brand {
  font-family: var(--pv-mono);
  font-size: var(--pv-size-small);
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--pv-accent);
  white-space: nowrap;
}
.pv-brand::before {
  content: '◆ ';
  color: var(--pv-accent);
  letter-spacing: 0;
}

.pv-nav {
  display: flex;
  gap: calc(var(--pv-u) * 1);
  align-items: center;
}

.pv-nav-link {
  font-family: var(--pv-mono);
  font-size: var(--pv-size-small);
  text-transform: lowercase;
  letter-spacing: 0.04em;
  color: var(--pv-text-muted);
  padding: calc(var(--pv-u) * 1) calc(var(--pv-u) * 2);
  border: 1px solid transparent;
  border-bottom: none;
  transition: color 120ms, background 120ms, border-color 120ms;
}
.pv-nav-link:hover {
  color: var(--pv-text);
  background: var(--pv-surface);
  border-color: var(--pv-border);
}
.pv-nav-link.is-active {
  color: var(--pv-accent);
  background: var(--pv-surface);
  border-color: var(--pv-border);
}

.pv-traffic {
  display: flex;
  gap: calc(var(--pv-u) * 1);
  align-items: center;
  margin-left: auto;
  font-family: var(--pv-mono);
  font-size: var(--pv-size-micro);
}

.pv-light {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--pv-text-dim);
  box-shadow: 0 0 0 1px var(--pv-border) inset;
}
.pv-light--green  { background: var(--pv-green);  box-shadow: 0 0 8px rgba(52,211,153,0.45); }
.pv-light--amber  { background: var(--pv-amber);  box-shadow: 0 0 8px rgba(251,191,36,0.45); }
.pv-light--red    { background: var(--pv-red);    box-shadow: 0 0 8px rgba(248,113,113,0.45); }
.pv-light--off    { background: var(--pv-text-dim); opacity: 0.45; }
.pv-light--blink  { animation: pv-blink 1.2s ease-in-out infinite; }
.pv-light--pulse  { animation: pv-pulse 2s ease-in-out infinite; }

@keyframes pv-blink {
  0%, 60% { opacity: 1; }
  80%, 100% { opacity: 0.25; }
}
@keyframes pv-pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.25); }
}

.pv-theme-toggle {
  margin-left: calc(var(--pv-u) * 2);
  background: transparent;
  border: var(--pv-hairline);
  color: var(--pv-text-muted);
  font-family: var(--pv-mono);
  font-size: var(--pv-size-micro);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: calc(var(--pv-u) * 1) calc(var(--pv-u) * 2);
  cursor: pointer;
  transition: color 120ms, border-color 120ms;
}
.pv-theme-toggle:hover {
  color: var(--pv-text);
  border-color: var(--pv-border-hi);
}

/* ============================================================
   Layout primitives
   ============================================================ */
.pv-wrap {
  position: relative;
  z-index: 1;
  max-width: 1400px;
  margin: 0 auto;
  padding: calc(var(--pv-u) * 6) calc(var(--pv-u) * 5);
}

.pv-page-title {
  display: flex;
  align-items: baseline;
  gap: calc(var(--pv-u) * 4);
  margin: 0 0 calc(var(--pv-u) * 5) 0;
  padding-bottom: calc(var(--pv-u) * 3);
  border-bottom: var(--pv-hairline);
}
.pv-page-title h1 {
  margin: 0;
  font-weight: 300;
  font-size: var(--pv-size-h1);
  letter-spacing: -0.01em;
}
.pv-page-title .pv-crumb {
  font-family: var(--pv-mono);
  font-size: var(--pv-size-small);
  color: var(--pv-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}
.pv-page-title .pv-crumb::before { content: '› '; color: var(--pv-accent); }

.pv-panel {
  background: var(--pv-surface);
  border: var(--pv-hairline);
  padding: calc(var(--pv-u) * 5);
}
.pv-panel--bare {
  background: transparent;
  border: var(--pv-hairline);
  padding: 0;
}

.pv-panel-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: calc(var(--pv-u) * 3) calc(var(--pv-u) * 4);
  background: var(--pv-surface-2);
  border-bottom: var(--pv-hairline);
}
.pv-panel-head h3 {
  margin: 0;
  font-family: var(--pv-mono);
  font-size: var(--pv-size-small);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-weight: 500;
  color: var(--pv-text-muted);
}

.pv-grid-2 {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: calc(var(--pv-u) * 6);
}
@media (max-width: 900px) {
  .pv-grid-2 { grid-template-columns: 1fr; }
}

/* ============================================================
   Form controls
   ============================================================ */
.pv-label {
  display: block;
  font-family: var(--pv-mono);
  font-size: var(--pv-size-micro);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--pv-text-muted);
  margin-bottom: calc(var(--pv-u) * 1);
}

.pv-input, .pv-select, .pv-textarea {
  width: 100%;
  background: var(--pv-bg);
  color: var(--pv-text);
  border: var(--pv-hairline);
  padding: calc(var(--pv-u) * 2) calc(var(--pv-u) * 3);
  font-family: var(--pv-sans);
  font-size: var(--pv-size-body);
  outline: none;
  transition: border-color 140ms, background 140ms;
}
.pv-input:focus, .pv-select:focus, .pv-textarea:focus {
  border-color: var(--pv-accent);
  background: var(--pv-surface);
  box-shadow: 0 0 0 3px var(--pv-accent-glow);
}
.pv-textarea {
  font-family: var(--pv-sans);
  resize: vertical;
  min-height: 4.5em;
  line-height: 1.5;
}
.pv-input--mono { font-family: var(--pv-mono); }

.pv-btn {
  display: inline-flex;
  align-items: center;
  gap: calc(var(--pv-u) * 2);
  background: var(--pv-accent);
  color: var(--pv-bg);
  font-family: var(--pv-mono);
  font-size: var(--pv-size-small);
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: calc(var(--pv-u) * 2) calc(var(--pv-u) * 4);
  border: none;
  cursor: pointer;
  transition: background 140ms, color 140ms, transform 60ms;
}
.pv-btn:hover { background: var(--pv-accent-dim); color: var(--pv-text); }
.pv-btn:active { transform: translateY(1px); }
.pv-btn[disabled] {
  background: var(--pv-surface-hi);
  color: var(--pv-text-dim);
  cursor: not-allowed;
}
.pv-btn--ghost {
  background: transparent;
  color: var(--pv-text-muted);
  border: var(--pv-hairline);
}
.pv-btn--ghost:hover {
  color: var(--pv-text);
  border-color: var(--pv-accent);
  background: transparent;
}
.pv-btn--danger { background: var(--pv-red); color: var(--pv-bg); }
.pv-btn--cinema {
  background: var(--pv-cinema);
  color: var(--pv-bg);
}

/* Style-chip radios — segmented control feel */
.pv-segmented {
  display: inline-flex;
  border: var(--pv-hairline);
  background: var(--pv-bg);
}
.pv-segmented label {
  padding: calc(var(--pv-u) * 2) calc(var(--pv-u) * 3);
  font-family: var(--pv-mono);
  font-size: var(--pv-size-micro);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--pv-text-muted);
  cursor: pointer;
  border-right: var(--pv-hairline);
  transition: color 120ms, background 120ms;
}
.pv-segmented label:last-child { border-right: none; }
.pv-segmented input[type="radio"] { display: none; }
.pv-segmented label:hover { color: var(--pv-text); }
.pv-segmented input:checked + .pv-seg-label,
.pv-segmented label.is-on {
  background: var(--pv-accent);
  color: var(--pv-bg);
}

/* When cinema is selected the segmented tint shifts */
.pv-segmented--cinema-on label.is-on { background: var(--pv-cinema); }

/* ============================================================
   Status ticker / telemetry chips
   ============================================================ */
.pv-chip {
  display: inline-flex;
  align-items: center;
  gap: calc(var(--pv-u) * 1);
  padding: calc(var(--pv-u) * 1) calc(var(--pv-u) * 2);
  background: var(--pv-surface-2);
  border: var(--pv-hairline);
  font-family: var(--pv-mono);
  font-size: var(--pv-size-micro);
  letter-spacing: 0.04em;
  color: var(--pv-text-muted);
}
.pv-chip--accent { color: var(--pv-accent); border-color: var(--pv-accent-dim); }
.pv-chip--cinema { color: var(--pv-cinema); border-color: var(--pv-cinema); }
.pv-chip strong {
  color: var(--pv-text);
  font-weight: 500;
}

.pv-chips {
  display: flex;
  flex-wrap: wrap;
  gap: calc(var(--pv-u) * 2);
  margin-bottom: calc(var(--pv-u) * 3);
}

.pv-meter {
  display: inline-flex;
  align-items: baseline;
  gap: calc(var(--pv-u) * 1);
  font-family: var(--pv-mono);
  font-size: var(--pv-size-micro);
  color: var(--pv-text-muted);
}
.pv-meter strong {
  font-feature-settings: "tnum" 1;
  color: var(--pv-text);
  font-weight: 500;
}

/* ============================================================
   Empty state + error banner
   ============================================================ */
.pv-empty {
  padding: calc(var(--pv-u) * 10);
  text-align: center;
  color: var(--pv-text-dim);
  font-style: italic;
  border: 1px dashed var(--pv-border);
  background: transparent;
}

.pv-error {
  padding: calc(var(--pv-u) * 3);
  border-left: 3px solid var(--pv-red);
  background: color-mix(in srgb, var(--pv-red) 8%, var(--pv-surface));
  color: var(--pv-text);
  font-family: var(--pv-mono);
  font-size: var(--pv-size-small);
}

/* ============================================================
   Utility
   ============================================================ */
.pv-hr { height: 1px; background: var(--pv-border); border: 0; margin: calc(var(--pv-u) * 5) 0; }
.pv-sp-1 { height: calc(var(--pv-u) * 2); }
.pv-sp-2 { height: calc(var(--pv-u) * 4); }
.pv-sp-3 { height: calc(var(--pv-u) * 6); }
.pv-row { display: flex; gap: calc(var(--pv-u) * 3); align-items: center; flex-wrap: wrap; }
.pv-row--end { justify-content: flex-end; }
.pv-row--between { justify-content: space-between; }

.pv-muted { color: var(--pv-text-muted); }
.pv-dim { color: var(--pv-text-dim); }
.pv-accent { color: var(--pv-accent); }
.pv-cinema { color: var(--pv-cinema); }
.pv-nowrap { white-space: nowrap; }
.pv-tabular { font-feature-settings: "tnum" 1; }