:root {
  --bg: #f2f5f6;
  --panel: #ffffff;
  --ink: #101c22;
  --ink-dim: #435057;
  --ink-faint: #7c8990;
  --line: #d3dcdf;
  --wire: #5c6f76;
  --north: #1f6f8b;
  --south: #b3562c;
  --serif: "Newsreader", Georgia, "Times New Roman", serif;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: "IBM Plex Mono", "SFMono-Regular", Consolas, monospace;
  --wrap: 760px;
}

* { box-sizing: border-box; }
html { background: var(--bg); }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 18px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 22px; }

.top { padding: 16px 22px; font-size: 14px; }
.top a { color: var(--ink-faint); text-decoration: none; }
.top a:hover { color: var(--north); }

.masthead { padding-top: 8px; padding-bottom: 12px; }
.kicker {
  font-family: var(--mono);
  font-size: 12.5px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--north);
  margin: 0 0 16px;
}
h1 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 52px;
  line-height: 1.08;
  margin: 0 0 18px;
  color: var(--ink);
  letter-spacing: -0.01em;
}
.deck {
  font-family: var(--serif);
  font-size: 22px;
  line-height: 1.48;
  color: var(--ink-dim);
  margin: 0 0 6px;
  font-weight: 500;
  font-style: italic;
}

article { padding-bottom: 8px; }
p { margin: 0 0 22px; color: var(--ink); }
p.lede { font-size: 20px; }
a { color: var(--north); }

h2 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 27px;
  margin: 0 0 16px;
  color: var(--ink);
}

.langbar { margin: 18px 0 6px; font-size: 14px; color: var(--ink-faint); }
.langbar a { color: var(--ink-dim); text-decoration: none; border-bottom: 1px solid var(--line); }
.langbar a:hover { color: var(--north); border-color: var(--north); }
.langbar .current { color: var(--north); }

/* --- instrument panel --- */
.instrument {
  margin: 44px 0 40px;
  padding: 30px 24px 26px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 4px;
  box-shadow: 0 1px 0 var(--line);
}
.instrument-caption {
  text-align: center;
  font-size: 14px;
  color: var(--ink-faint);
  margin: 0 0 22px;
}

.lat-row {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 22px;
}
.lat-row input[type="range"] { flex: 1; accent-color: var(--north); }
.lat-readout {
  font-family: var(--mono);
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
  min-width: 92px;
  text-align: right;
}

.preset-row {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-bottom: 26px;
  flex-wrap: wrap;
}
.preset-btn {
  font-family: var(--sans);
  font-size: 13.5px;
  font-weight: 600;
  padding: 7px 14px;
  border: 1px solid var(--line);
  background: var(--bg);
  color: var(--ink-dim);
  border-radius: 18px;
  cursor: pointer;
}
.preset-btn:hover { border-color: var(--ink-faint); color: var(--ink); }

.vortex-wrap { padding: 6px 4px 2px; display: flex; justify-content: center; }
.vortex-wrap svg { width: 100%; max-width: 320px; height: auto; display: block; overflow: visible; }
.vortex-arm { fill: none; stroke-linecap: round; }
.vortex-center { fill: var(--wire); }

.stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: 4px;
  overflow: hidden;
  margin: 22px 0 8px;
}
.stat { background: var(--panel); padding: 20px 14px; text-align: center; }
.stat .num { font-family: var(--mono); font-size: 22px; font-weight: 600; color: var(--ink); display: block; }
.stat .lbl { font-size: 12.5px; color: var(--ink-faint); margin-top: 6px; display: block; line-height: 1.4; }

.gap-caption { text-align: center; font-family: var(--mono); font-size: 13.5px; color: var(--south); margin-top: 18px; font-weight: 600; }

.method {
  font-size: 14.5px;
  color: var(--ink-faint);
  border-top: 1px solid var(--line);
  padding-top: 20px;
  margin-top: 8px;
}

.sourcelist { font-size: 15px; }
.sourcelist li { margin-bottom: 10px; }

footer.wrap { padding: 30px 22px 60px; font-size: 13.5px; color: var(--ink-faint); }
footer a { color: var(--ink-dim); }

@media (max-width: 480px) {
  h1 { font-size: 34px; }
  .deck { font-size: 18.5px; }
  body { font-size: 16.5px; }
  .stats { grid-template-columns: 1fr; }
  .lat-row { flex-wrap: wrap; }
  .lat-readout { min-width: 100%; text-align: left; order: -1; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
  .vortex-arm { animation: none !important; }
}