:root {
  --bg: #0e1116;
  --bg-elev: #161a22;
  --bg-elev-2: #1d222d;
  --fg: #e6e6e6;
  --fg-dim: #9aa3b2;
  --fg-faint: #6b7280;
  --border: #262c38;
  --border-strong: #353c4d;

  --us: #4ade80;
  --eu: #60a5fa;
  --ap: #f472b6;

  --ok: #4ade80;
  --warn: #fbbf24;
  --err: #f87171;

  --mono: ui-monospace, "JetBrains Mono", "Menlo", "Monaco", "Consolas", monospace;
  --sans: ui-sans-serif, system-ui, -apple-system, "Segoe UI", "Inter", sans-serif;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--sans);
  font-size: 14px;
  line-height: 1.45;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 24px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-elev);
}
header h1 { font-size: 16px; font-weight: 600; margin: 0; letter-spacing: -0.01em; }
.header-meta { display: flex; align-items: center; gap: 16px; }
.header-spacer { width: 1px; height: 14px; background: var(--border); }
.link-btn {
  background: transparent;
  border: 1px solid var(--border-strong);
  color: var(--fg-dim);
  font-family: var(--mono);
  font-size: 12px;
  padding: 5px 10px;
  border-radius: 4px;
  cursor: pointer;
  text-decoration: none;
}
.link-btn:hover { color: var(--fg); border-color: var(--fg-dim); }

.conn-status {
  font-family: var(--mono);
  font-size: 12px;
  padding: 4px 10px;
  border-radius: 999px;
  border: 1px solid var(--border);
}
.conn-pending { color: var(--warn); border-color: var(--warn); }
.conn-ok      { color: var(--ok);   border-color: var(--ok); }
.conn-err     { color: var(--err);  border-color: var(--err); }

main {
  flex: 1;
  padding: 18px 24px 30px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  max-width: 1700px;
  width: 100%;
  margin: 0 auto;
}

/* settings */
.settings-panel {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  padding: 14px 20px;
  margin: 0 24px;
  border-radius: 6px;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: end;
}
.settings-panel.hidden { display: none; }
.settings-panel label {
  display: flex;
  flex-direction: column;
  gap: 4px;
  font-size: 12px;
  color: var(--fg-dim);
  flex: 1 1 280px;
}
.settings-panel input {
  background: var(--bg-elev-2);
  color: var(--fg);
  border: 1px solid var(--border-strong);
  border-radius: 4px;
  padding: 6px 9px;
  font-family: var(--mono);
  font-size: 13px;
}
.settings-panel button {
  background: var(--bg-elev-2);
  color: var(--fg);
  border: 1px solid var(--border-strong);
  border-radius: 4px;
  padding: 7px 14px;
  cursor: pointer;
  font-size: 12px;
}
.settings-panel button:hover { border-color: var(--fg-dim); }
.hint {
  font-size: 11px;
  color: var(--fg-faint);
  margin: 6px 0 0;
}

/* region columns */
.regions {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}
.region {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 12px 14px;
  min-height: 380px;
}
.region h2 {
  font-size: 13px;
  font-weight: 600;
  margin: 0 0 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.region-tag {
  display: inline-block;
  padding: 2px 7px;
  font-size: 11px;
  font-family: var(--mono);
  border-radius: 4px;
  background: var(--bg-elev-2);
  color: var(--fg-dim);
  border: 1px solid var(--border-strong);
}
.region-us { color: var(--us); border-color: color-mix(in srgb, var(--us) 60%, var(--border-strong)); }
.region-eu { color: var(--eu); border-color: color-mix(in srgb, var(--eu) 60%, var(--border-strong)); }
.region-ap { color: var(--ap); border-color: color-mix(in srgb, var(--ap) 60%, var(--border-strong)); }

.region-body {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.kv {
  background: var(--bg-elev-2);
  border-radius: 4px;
  padding: 8px 10px;
  border: 1px solid var(--border);
}
.kv-label {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--fg-faint);
  margin-bottom: 4px;
}
.kv-value {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--fg);
  white-space: pre-wrap;
  word-break: break-word;
}
.kv-value.empty { color: var(--fg-faint); font-style: italic; }
.kv-just-changed {
  animation: flash 1.4s ease-out;
}
@keyframes flash {
  0%   { background: color-mix(in srgb, var(--us) 25%, var(--bg-elev-2)); }
  40%  { background: color-mix(in srgb, var(--us) 18%, var(--bg-elev-2)); }
  100% { background: var(--bg-elev-2); }
}

/* bottom grid: log + sim + produce */
.bottom-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 12px;
  min-height: 320px;
}
@media (max-width: 1100px) {
  .bottom-grid { grid-template-columns: 1fr; }
}
.event-log, .produce, .sim {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 12px 14px;
}

/* sim controls */
.sim-header { display: flex; justify-content: space-between; align-items: center; }
.sim-status {
  font-family: var(--mono);
  font-size: 11px;
  padding: 3px 8px;
  border-radius: 999px;
  border: 1px solid var(--border);
}
.sim-off { color: var(--fg-faint); border-color: var(--border-strong); }
.sim-on  { color: var(--ok); border-color: var(--ok); }
.sim-controls {
  display: flex;
  gap: 8px;
  align-items: end;
  margin-top: 10px;
}
.sim-controls label {
  display: flex;
  flex-direction: column;
  gap: 3px;
  font-size: 11px;
  color: var(--fg-dim);
  flex: 1;
}
.sim-controls button {
  background: var(--bg-elev-2);
  color: var(--fg);
  border: 1px solid var(--border-strong);
  border-radius: 4px;
  padding: 8px 16px;
  cursor: pointer;
  font-size: 12px;
  min-width: 90px;
}
.sim-controls button:hover { border-color: var(--fg-dim); }
.sim-controls button.running {
  border-color: var(--err);
  color: var(--err);
}
.sim-controls button:disabled { opacity: 0.5; cursor: not-allowed; }
.sim-stats {
  margin-top: 10px;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--fg-dim);
}
.event-log-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.event-log h2, .produce h2 { font-size: 13px; font-weight: 600; margin: 0; }
.event-log-stats {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--fg-dim);
  display: flex;
  align-items: center;
  gap: 10px;
}

#event-log {
  margin-top: 10px;
  max-height: 460px;
  overflow-y: auto;
  font-family: var(--mono);
  font-size: 12px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.evt {
  padding: 5px 8px;
  border-radius: 4px;
  background: var(--bg-elev-2);
  border-left: 3px solid var(--border-strong);
  display: grid;
  grid-template-columns: auto auto auto 1fr auto;
  gap: 10px;
  align-items: center;
}
.evt-origin-us { border-left-color: var(--us); }
.evt-origin-eu { border-left-color: var(--eu); }
.evt-origin-ap { border-left-color: var(--ap); }

.evt-time   { color: var(--fg-faint); font-size: 11px; min-width: 64px; }
.evt-origin { font-weight: 600; min-width: 24px; }
.evt-origin.us { color: var(--us); }
.evt-origin.eu { color: var(--eu); }
.evt-origin.ap { color: var(--ap); }
.evt-op     { color: var(--fg); min-width: 44px; }
.evt-key    { color: var(--fg); }
.evt-payload { color: var(--fg-dim); }
.evt-observed {
  display: inline-flex;
  gap: 3px;
  font-size: 10px;
  color: var(--fg-faint);
}
.evt-observed .obs {
  display: inline-block;
  width: 6px;
  height: 12px;
  background: var(--border-strong);
  border-radius: 1px;
  opacity: 0.4;
}
.evt-observed .obs.us { background: var(--us); opacity: 1; }
.evt-observed .obs.eu { background: var(--eu); opacity: 1; }
.evt-observed .obs.ap { background: var(--ap); opacity: 1; }

/* produce form */
#produce-form {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 8px;
}
.row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.row label {
  display: flex;
  flex-direction: column;
  gap: 3px;
  font-size: 11px;
  color: var(--fg-dim);
  flex: 1 1 80px;
}
.row label:has(input[name="key"]),
.row label:has(input[name="value"]) { flex: 2 1 200px; }
input, select {
  background: var(--bg-elev-2);
  color: var(--fg);
  border: 1px solid var(--border-strong);
  border-radius: 4px;
  padding: 6px 8px;
  font-family: var(--mono);
  font-size: 12px;
}
.produce-actions {
  align-items: center;
}
button[type="submit"] {
  background: var(--bg-elev-2);
  color: var(--fg);
  border: 1px solid var(--border-strong);
  border-radius: 4px;
  padding: 8px 16px;
  cursor: pointer;
  font-size: 12px;
}
button[type="submit"]:hover { border-color: var(--fg-dim); }
button[type="submit"]:disabled { opacity: 0.5; cursor: not-allowed; }

.produce-result {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--fg-dim);
}
.produce-result.ok  { color: var(--ok); }
.produce-result.err { color: var(--err); }

footer {
  padding: 12px 24px;
  border-top: 1px solid var(--border);
  background: var(--bg-elev);
  font-size: 11px;
  color: var(--fg-faint);
  text-align: center;
}

/* prose / how-it-works page */
main.prose {
  max-width: 760px;
  margin: 0 auto;
  padding: 32px 24px 48px;
  display: block;
  font-size: 15px;
  line-height: 1.65;
  color: var(--fg);
}
main.prose section + section { margin-top: 36px; }
main.prose h2 {
  font-size: 22px;
  font-weight: 600;
  margin: 0 0 14px;
  letter-spacing: -0.01em;
  border-bottom: 1px solid var(--border);
  padding-bottom: 8px;
}
main.prose h3 { font-size: 16px; font-weight: 600; margin: 24px 0 8px; }
main.prose p { margin: 0 0 14px; color: var(--fg); }
main.prose strong { color: var(--fg); font-weight: 600; }
main.prose em { color: var(--fg-dim); font-style: italic; }
main.prose a { color: var(--eu); text-decoration: underline; text-decoration-color: color-mix(in srgb, var(--eu) 35%, transparent); text-underline-offset: 2px; }
main.prose a:hover { text-decoration-color: var(--eu); }

main.prose ul, main.prose ol {
  margin: 0 0 14px;
  padding-left: 22px;
}
main.prose li { margin-bottom: 6px; }
main.prose ol.trace { counter-reset: step; padding-left: 0; list-style: none; }
main.prose ol.trace > li {
  counter-increment: step;
  position: relative;
  padding: 10px 12px 10px 42px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 6px;
  margin-bottom: 8px;
}
main.prose ol.trace > li::before {
  content: counter(step);
  position: absolute;
  left: 12px;
  top: 10px;
  width: 22px;
  height: 22px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-elev-2);
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--fg-dim);
}

main.prose code {
  font-family: var(--mono);
  font-size: 0.86em;
  background: var(--bg-elev-2);
  padding: 1px 5px;
  border-radius: 3px;
  color: var(--fg);
}
main.prose pre {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 14px 16px;
  overflow-x: auto;
  margin: 0 0 14px;
  line-height: 1.45;
}
main.prose pre code {
  background: transparent;
  padding: 0;
  font-size: 12.5px;
  color: var(--fg);
}
main.prose pre.diagram {
  font-size: 12px;
  line-height: 1.3;
  color: var(--fg-dim);
}

main.prose table {
  width: 100%;
  border-collapse: collapse;
  margin: 0 0 16px;
  font-size: 13.5px;
}
main.prose table th, main.prose table td {
  text-align: left;
  vertical-align: top;
  padding: 8px 12px;
  border-bottom: 1px solid var(--border);
}
main.prose table th {
  font-weight: 600;
  color: var(--fg);
  background: var(--bg-elev);
  border-bottom: 1px solid var(--border-strong);
}
main.prose table tr:hover td { background: var(--bg-elev); }

main.prose section.closing {
  margin-top: 40px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
  color: var(--fg-faint);
  font-size: 13px;
}